RetouchPRO

Go Back   RetouchPRO > Tools > Software
Register Blogs FAQ Site Nav Search Today's Posts Mark Forums Read


Software Photoshop, Lightroom, Paintshop Pro, Painter, etc., and all their various plugins. Of course, you can also discuss all other programs, as well.

Converting 8 bit images to 16 bit - any benefits?

Reply
 
Thread Tools
  #21  
Old 07-27-2011, 02:07 AM
kav kav is offline
Senior Member
 
Join Date: May 2009
Posts: 574
Re: Converting 8 bit images to 16 bit - any benefi

I get the examples. It just seemed like only a proof of concept rather than a realistic workflow situation. I won't go further in depth on this as I don't want to derail a constructive thread onto the topic of color profiles.
Reply With Quote top
  #22  
Old 07-27-2011, 09:08 AM
andrewrodney's Avatar
andrewrodney andrewrodney is offline
Senior Member
 
Join Date: May 2010
Location: Santa Fe
Posts: 1,091
Re: Converting 8 bit images to 16 bit - any benefi

About the only time one may be stuck converting sRGB into ProPhoto is if you are building a composite image who’s parts are in ProPhoto RGB. Someone supplies you data in sRGB and that’s all they have. Its akin to those who unfortunately are handed a CMYK document and have to composite it into an RGB document. When someone hands you lemons, you try to make lemonade.
Reply With Quote top
  #23  
Old 07-27-2011, 09:20 AM
Repairman's Avatar
Repairman Repairman is offline
Senior Member
 
Join Date: Dec 2010
Location: Bristol UK
Posts: 683
Re: Converting 8 bit images to 16 bit - any benefi

Nice demo John. It provides a compelling reason to work in 16bit. Applying the same test to two images images where grads do not feature significantly, would we still notice a difference in quality. (I mean in commercial terms rather than 'in theory').
R.
Reply With Quote top
  #24  
Old 07-27-2011, 11:04 AM
John Wheeler's Avatar
John Wheeler John Wheeler is offline
Senior Member
 
Join Date: May 2011
Location: Colorado
Posts: 583
Re: Converting 8 bit images to 16 bit - any benefi

Quote:
Originally Posted by kav View Post
I get the examples. It just seemed like only a proof of concept rather than a realistic workflow situation. I won't go further in depth on this as I don't want to derail a constructive thread onto the topic of color profiles.
Hi Kav
Thanks for your additional comments.
Let me add a change to the last example to make it more realistic and a recommended and documented workflow (at least by some).

Before that let me say that I actually do not recommend making many of these adjustments in LAB and personally recommend using ACR or Lightroom even for adjustments on JPG and TIF files as the front end process. Those tools are very intuitive, non destructive, is done in high bit, and you can bring them into Photoshop as a Smart Object so you can have re-dos.
I also know that there are large number of Photoshop users that do not use Lightroom or ACR and continue to edit 8 bit images in 8 bit mode. I am just trying to put more information out there through examples so that readers/Photoshop users have a little more info of what lurks from within to make better decisions on their own workflow.

Degradation Case #3

This will be the same as my last post with simply replacing the two duplicated layers with multiply blend with a simple Levels Adjustments. This is a workflow that has been recommended by those steeped in LAB as a way to adjust luminosity without changing Hue/Sat.

For first iamge
- Open 8 bit sRGB image into Photoshop and keep sRGB as the same working space
- Convert to Lab mode (still in 8 bit mode)
- Add Levels Adjustment Layer
- Flatten
- Convert to Profile back to sRGB

Here is a 100% view around the sun of the image. Notice that there is some banding. The banding is visible in prints.

Sunset 8 bit sRGB rountrip to Lab One Levels Adj.jpg

Next image was created with these steps:
- Open 8 bit sRGB image into Photoshop and keep sRGB as the same working space
- Convert to 16 bit mode
- Convert to Lab mode (still in 8 bit mode)
- Add Levels Adjustment Layer with same settings as previous image
- Flatten
- Convert to Profile back to sRGB
- Convert back to 8 bit mode

Here is the resulting image going roundtrip to Lab in 16 bit mode. Note that there is less banding:

Sunset 16 bit sRGB rountrip to Lab One Levels Adj.jpg

The same conditions I mentioned from my prior post need to occur to see this banding e.g. low noise image and turn off dithering, viewing at 100%.

What was very interesting (and can be educational) about using this particular experiment in 8 bit mode is that as you move the sliders in the Lab Levels Adjustment Layer the banding streaks across the image like a psychedelic show. Sometimes single bands and sparse and sometimes a whole bunch. If you are not convinced there is an issue, this is the experiment for you.
Reply With Quote top
  #25  
Old 07-27-2011, 11:40 AM
John Wheeler's Avatar
John Wheeler John Wheeler is offline
Senior Member
 
Join Date: May 2011
Location: Colorado
Posts: 583
Re: Converting 8 bit images to 16 bit - any benefi

Quote:
Originally Posted by Repairman View Post
Nice demo John. It provides a compelling reason to work in 16bit. Applying the same test to two images images where grads do not feature significantly, would we still notice a difference in quality. (I mean in commercial terms rather than 'in theory').
R.
Hi R and thanks for your comments and thoughts. Good question about does it make a difference on a commercial basis and for images without slow low noise gradients. First let me say that visible issues can also occur in other situations as well. The most noticeable is losing details in shadows or highlights depending on how the processing was done. More on that later in additional posts when I can get to it.

Here is an analogy: Is it OK to drive without wearing a seat-belt? The vast majority of the time it is not an issue and it is a hassle to buckle up every time (try buckling in 3 very young grandchildren into car seats and you will understand the hassle ).

I would say that for many images there is not an issue. This is very similar to that many times working with JPGs is not an issue and just working with 8 bit JPGs out of your camera instead of RAW works most of the time too.

To me it is a time saver. I have been bit when editing 8 bit images in 8 bit mode several times and had to do rework. It was just a question was I willing to just go to 16 bit mode and double file sizes in general or just live with the occasional rework. I made the move to 16 bit for most cases and did not look back - no regrets for me. Yes there are cases where I just stay in 8 bit mode when I know if there were some subtle quality issues that it did not matter. When the quality mattered and I did not want to risk rework, I just stick with 16 bit.

If you have done lots of work and have never seen an issue, that is a good indicator that the type of images that you take and the workflow you use does not introduce a problem so your risks are pretty low of having an issue. The client may not notice or care if you had slight banding or loss of detail in shadows or highlights as well. So it is image, workflow, and client dependent whether it should be a concern for you or any other member.

I personally like the idea that I don't have to scour my images in every corner looking for these "8 bit image processed in 8 bit mode anomalies".

Such degradation is there in every 8 bit image processed in 8 bit mode, yet between the human eye and already existing or Photoshop introduced noise one does not see it most of the time - just like high quality JPEG compression. It is usually not an issue until you come across one you see and you say "what the @#$% is that?" and then move on to rework.

Thank you for you comments because I am hoping to move the discussion from "there is no degradation" to "yes there is degradation yet does it become visible with ones images and workflow often enough to be considered an issue that suggests staying in 16 bit would be a good idea." For me it did yet your mileage may vary.
Reply With Quote top
  #26  
Old 07-27-2011, 04:37 PM
John Wheeler's Avatar
John Wheeler John Wheeler is offline
Senior Member
 
Join Date: May 2011
Location: Colorado
Posts: 583
Re: Converting 8 bit images to 16 bit - any benefi

Degradation Case 4

Multiply Blend is "Extreme?"

It has been said on occasion that as long as you don't do anything "extreme", then processing 8 bit images in 8 bit mode is just fine. Of course the definition of extreme is not written down anywhere and usually it comes up when you have an image anomaly processing 8 bit images in 8 bit mode and someone helpfully tells you that you must have done something "extreme."

This degradation case is simply a mulitply blend followed by a curves adjustment Layer showing degradation in 8 bit that is dramatically less in 16 bit mode - I guess I am being "extreme"

Here is the base image at reduced resolution that I obtained from Stock Exhange: http://www.sxc.hu/photo/1138961 This image is in Adobe RGB and all I did for the starting point Convert to Profile...sRGB for consistency with the other cases.

Here is a reduced resolution version of the original.

Attachment 87808

Please notice the clocks in the shadows in the lower left corner on the clock tower.

A common technique for darkening an image and getting a certain effect is just to duplicate the image layer and apply a multiply blend. Here is that image:

Attachment 87809

Note that the clocks that were in the shadow are in the dark. I am just going to use a curves Adjustment Layer to recover those shadows in the following steps.

First here is a 100% of the original image. I did brighten it up by 2X to make it easier to see by using a Curves Adjustment Layer with white point at 128. You can see that the shadows have details:

Multiply is Extreme clocks 100% original 2X brightened.jpg

Here are the steps to create the following image.
- Convert to 16 bit mode
- Duplicate Image Layer and set Blend to Multiply
- Use Curves Adjustment Layer so Shadows to pull back the image similar to original.
- Brighten by 2X with another curves adjustment Layer for display on ReTouch Pro for better visibility (this extra step does not create degradation).
- Convert back to 8 bit mode

I targeted the clockface to have the same luminosity as the original. There is slightly higher tonal range due to the multiply:

Multiply is Extreme clocks 100% 16 bit Multiply plus curves 2X brightened.jpg

Now I repeated the steps in 8 bit mode
- No Conversion of bit mode it was already in 8 bit
- Duplicate Image Layer and set Blend to Multiply
- Use Curves Adjustment Layer so Shadows to pull back the image similar to original (same settings as previous image)
- Brighten by 2X with another curves adjustment Layer for display on ReTouch Pro for better visibility (this extra step does not create degradation):

Multiply is Extreme clocks 100% 8 bit Multiply plus curves 2X brightened.jpg

Now that's an image that only a parent or grandparent could love

So why such a large degradation for an 8 bit image in 8 bit mode processing. Turns out that Multiply/Screen blend is quite extreme blend in the shadows/highlights respectively.

For Mulitply Blend in 8bit mode all color pixel values at or below 37 out of 256 (~15% of your tonality) will be compressed down to the levels of 0 thru 5. So this causes posterization in the shadows of about 7X. When reversing course and trying to recover the shadows, the posterization remains.

In 16 bit Multiply Blend, that same tonality range up to 37 is compressed down to ~1400 levels (in 16 bit increments) due to the finer resolution of 16 bit mode. When recovering the shadows, virtually all the detail is still there.

Are there ways to avoid this in 8 bit mode. YES. Is the average Photoshop User aware of what to do - Based on my polling - NO. Basically, its best to avoid the pushing of pixels darker/lighter and then pushing them again lighter/darker respectively.

Now, who among us actually understands what is "Extreme" that will cause issues for 8 bit images in 8 bit mode with all the various Adjustment Layers, Blends, Layer Styles and their combinations among them against different image types. My background in Photoshop is from a forensics standpoint to understand when an operation actually reveals something valuable vs just introducing an anomaly. Even with 5 years of studying the details of the Photoshop operations from this standpoint I will not even make that claim of a complete understanding of what causes "Extreme." All I know is that I keep discovering more cases all the time.

Now you may ask "Are there any more types of anomalies in 8 bit processing of 8 bit images. YES. The most common is increased additional image noise. Every operation in Photoshop has what is called rounding errors with each operation creating a little more noise with each operation. Some of the noise cancels each other out and some does not. If each pixel experiences just a few operations, you would most likely not see the issue. On the other hand, if each pixel experiences 100 operations (heavy duty Layer Stack, blends etc) then it can be noticeable.

In 8 bit mode an error on the order of +/- (1/512) is introduced with each operation. In 16 bit the error introduced with each operation is +/- (1/131,072). A much smaller error to be accumulating with less introduction of this rounding noise.

I do not time to post another example showing this noise at this point and if there is strong interest I could do so yet wouldn't be until after next week.

So should you process 8 bit images in 16 bit mode? Hopefully this and the previous posts will provide some practical examples to help you make a decision that works best for you and your workflow.

Thanks for putting up with my long posts. I hope this was useful to someone (besides to read and help you go to sleep at night zzzzzzzzz )
Reply With Quote top
  #27  
Old 08-11-2011, 03:33 PM
Tony W's Avatar
Tony W Tony W is offline
Senior Member
Patron
 
Join Date: Mar 2010
Posts: 1,415
Re: Converting 8 bit images to 16 bit - any benefi

It has taken me quite a long time to reply to this thread (due to personal reasons causing me to have limited time). Please accept my apologies particularly John as you obviously went to some trouble and spent a lot of time with your response. I have to say that I have not actually repeated your efforts although I did not follow exactly your procedure

I have only gone so far with this looking at the first case.

Degradation case 1

The original image without adjustment shows obvious signs of posterisation therefore normally care should be taken in handling.

Using the image you posted from photobucket followed I think your example with one exception I did not go into ProPhoto RGB for the reason that banding could be worsened.

I normally leave Dither on but in this case turned off to better mimic your tests:
Steps taken for my image:
  • Saved image as is from Photobucket flagged as sRGB
  • Opened in Photoshop as original 8 bit sRGB
  • Duplicated and converted this to 16 bit
  • 8 Bit background layer duplicated and set blend to Screen
  • Dragged the duplicate layer down to copy. Ending up with 3 layers background, layer 1 and 2 both set to screen blend
  • Flattened image
  • Edit > Convet to sRGB profile ( I know I was already there but wanted to copy your workflow)
  • Followed the above for the 16 bit conversion.
My attachments show what I got - but I have to say that the save for web conversion seems to have thrown something into the mix as these images matched exactly on screen. I have not tried printing yet but I think you may agree that if there is a difference it is very difficult to see.

In fact in positioning the second image I was unsure which was which (should have named the layers better)

I have not tried your second or third degradation examples due to time constraints and the fact that LAB has been thrown into the frame.

Generally I am happy to work in LAB where I think the image would benefit. In this case however I can think of no benefit or reason to turn to LAB, I would not want to brighten or separate the colours for instance.

There has been much discussion/controversy about LAB conversion FWIW I have not noticed so far any losses worth worrying about on the images I have tackled, but I do not support the view that the image has not lost anything – I understand that 20-30 levels may be lost in the first conversion – so something has gone but in some cases this may not be missed, for others it may be important?

Quote:
I personally like the idea that I don't have to scour my images in every corner looking for these "8 bit image processed in 8 bit mode anomalies".
I can appreciate this viewpoint
Attached Images
File Type: jpg Johns8bit16bit.jpg (97.8 KB, 7 views)
File Type: jpg Johns8bit16bit2.jpg (89.7 KB, 6 views)

Last edited by Tony W; 08-11-2011 at 04:10 PM.
Reply With Quote top
  #28  
Old 08-11-2011, 05:44 PM
John Wheeler's Avatar
John Wheeler John Wheeler is offline
Senior Member
 
Join Date: May 2011
Location: Colorado
Posts: 583
Re: Converting 8 bit images to 16 bit - any benefi

Hi Tony
Sorry but your post made me smile a bit. Here is a quote from your post:
Quote:
Originally Posted by Tony W View Post
......Degradation case 1
Using the image you posted from photobucket followed I think your example with one exception I did not go into ProPhoto RGB for the reason that banding could be worsened.
Yet in my post for Degradation Case 1:

Quote:
Originally Posted by John Wheeler View Post
Degradation Case 1
So here is a case where you will see banding degradation when an 8 bit image is processed in 8 bit mode yet not when it is processed in 16 bit mode. This occurs when this 8 bit sRGB image is converted to a working space of ProPhoto RGB.
So of course, if my case is to show the degradation differences between 8 bit mode and 16 bit mode when going to ProPhoto RGB, and you eliminate the step of going to ProPhoto RGB space (the whole point for this degradation case), of course you will not see the same result

So I apologize if I missed your point, yet what is your point?

Just to summarize what I was trying to indicate. There has been long standing discussions that converting 8 bit images to 16 bit makes no difference in image quality. I would agree with that until ones start to do additional Photoshop processing. With additional processing, there can be a visible difference if taking an 8 bit image and staying in 8 bit mode for additional processing vs taking a 8 bit image and converting to 16 bit before doing additional processing. I presented just 4 degradation cases (and there are many more) where there is visible degradation. Here is the combined summary of those 4 cases:

Case 1: Taking an sRGB image and processing in ProPhoto RGB space and back to sRGB. There are many Photoshop users that have their Color Settings set to a default color space of ProPhoto RGB or take JPEG images through Lightroom or ACR into Photoshop as ProPhoto RGB with no flags set to let you know you are converting from sRGB to a wider gamut space. Then when outputting to Web or for printing it is converted to sRGB again. Not all images will show degradation yet I documented the types of images that very likely would.

Case 2/Case 3: This was moving an sRGB image to LAB for special processing and then back to RGB. Repairman indicated that Case 2 may not be common ("in theory") so I included Case 3 following steps right out of Lab books. Again, not every image will have visible degradation yet again, I indicated the types of images where where degradation would be visible.

Case 4: This case showed degradation while staying in just sRGB and not changing color spaces using a simple multiply blend and Curves Adjustment Layer. I have seen these steps documented in many Photoshop books so assume many Photoshop users may follow these same steps. Not all images will show visible degradation yet again, I documented the cases in which the degradation would be visible.

There is a myth that moving 8 bit images to 16 bit mode has no visible quality advantages for normal additional Photoshop processing. For many images that is true. To make that a blanket statement for all images is just that - a myth and is simply not true (IMHO ). So should everyone just use 16 bit - NO. There are tradeoffs with file size, processing speed, and available functionality in Photoshop. Just don't depend on that myth to cover your rear and assume that it never matters.

Now as a side note - Tony, the images that you were allowed to download from my Photobucket account were apparently not full resolution. I don't know why my account did not allow a full resolution download for you. I checked and the lower resolution images for Degradation Case 1 worked the same at lower resolution as well (if you follow all the steps ). For anyone wanting the full resolution images for any of the cases just send me a PM and I will figure a way to send them through either email or another posting mechanism.
Reply With Quote top
  #29  
Old 08-12-2011, 07:36 AM
Tony W's Avatar
Tony W Tony W is offline
Senior Member
Patron
 
Join Date: Mar 2010
Posts: 1,415
Re: Converting 8 bit images to 16 bit - any benefi

Quote:
Sorry but your post made me smile a bit.
No need to be sorry, always glad to bring a smile to someone’s face even when I do it inadvertently
So that I do not take anything out of context (hopefully) I will use your reply as my basis and offer explanation comment where appropriate

Quote:
So of course, if my case is to show the degradation differences between 8 bit mode and 16 bit mode when going to ProPhoto RGB, and you eliminate the step of going to ProPhoto RGB space (the whole point for this degradation case), of course you will not see the same result
My turn to be sorry John but I totally missed the point and should have studied your reply more thoroughly before responding. In the event I saw that the move was in Prophoto and it looked like you had just decided to convert to this for no apparent reason other than your standard working space. If I had properly read your earlier statement you did make it clear that the degradation can occur with 8 bit sRGB is converted to ProPhoto RGB - a fact that I can attest to

Quote:
So I apologize if I missed your point, yet what is your point?
If you did miss my point (although I do not think this to be the case) the blame can only be laid at my feet. To ask what is my point further strengthens the case that I have perhaps been a little vague in my first post.

Two reasons for this, first I was trying not to be too ‘wordy’ and keep my question short and concise. Secondly I was attempting not to be prescriptive as I was looking for other opinion which may or may not coincide with my own.

So the points I set out to try and clarify were:
  • Any real benefit taking an 8 bit file and editing in 16 bit workspace and potential pitfalls. Some ‘gotchas’ I was already aware of and which you have highlighted in your replies.
  • Is it possible that 8 bit to 16 bit could degrade image due to moving to the higher bit depth. This thought stemmed from a conversation with another PS user who was quite adamant that due to losing so many levels there were huge gaps in the histogram and these were not evident in the PS histogram views. Further he maintained that these gaps could be ‘repaired’ with a plug in (name unknown) he used, therefore avoiding potential image degradation problems. My first thoughts were that he had bought into buying ‘snake oil’. How could a histogram be repaired other than perhaps to interpolate the missing information in the gaps and would this actually make an observable difference? Perhaps these thoughts were unfair and incorrect and the application may offer something?
Quote:
Case 1: Taking an sRGB image and processing in ProPhoto RGB space and back to sRGB. There are many Photoshop users that have their Color Settings set to a default color space of ProPhoto RGB or take JPEG images through Lightroom or ACR into Photoshop as ProPhoto RGB with no flags set to let you know you are converting from sRGB to a wider gamut space. Then when outputting to Web or for printing it is converted to sRGB again. Not all images will show degradation yet I documented the types of images that very likely would.
My default colour space is ProPhoto RGB but all flags are set to warn of conversion mismatch. But can understand the warning for the unwary.

Quote:
Case 2/Case 3: This was moving an sRGB image to LAB for special processing and then back to RGB. Repairman indicated that Case 2 may not be common ("in theory") so I included Case 3 following steps right out of Lab books. Again, not every image will have visible degradation yet again, I indicated the types of images where where degradation would be visible.
Not really had time to study these but I am sure will be of interest.

Quote:
Case 4: This case showed degradation while staying in just sRGB and not changing color spaces using a simple multiply blend and Curves Adjustment Layer. I have seen these steps documented in many Photoshop books so assume many Photoshop users may follow these same steps. Not all images will show visible degradation yet again, I documented the cases in which the degradation would be visible.
Again need to have a proper look at this. Multiply blend is something that I rarely need to use these days but I think I see where you are coming from

Quote:
There is a myth that moving 8 bit images to 16 bit mode has no visible quality advantages for normal additional Photoshop processing. For many images that is true. To make that a blanket statement for all images is just that - a myth and is simply not true (IMHO). So should everyone just use 16 bit - NO. There are tradeoffs with file size, processing speed, and available functionality in Photoshop. Just don't depend on that myth to cover your rear and assume that it never matters.
I can appreciate your points here and to make generalised statement is wrong without pointing out where these generalisations may fall apart. I can also understand that it may be worthwhile in switching to 16 bit to attempt to cover your rear. The tradeoffs with file size and processing speed are not a huge concern to me at least. Functionality loss may be problematical at times and then there is the fact that it is likely that you will need to output at some time back in 8 bit.


Quote:
Now as a side note - Tony, the images that you were allowed to download from my Photobucket account were apparently not full resolution.
No problem John I do not think it too important as I can see where you are coming from and me taking the same actions will result in what you have demonstrated.
Reply With Quote top
  #30  
Old 08-12-2011, 11:24 AM
John Wheeler's Avatar
John Wheeler John Wheeler is offline
Senior Member
 
Join Date: May 2011
Location: Colorado
Posts: 583
Re: Converting 8 bit images to 16 bit - any benefi

Quote:
Originally Posted by Tony W View Post
Two reasons for this, first I was trying not to be too ‘wordy’ and keep my question short and concise.
Unfortunately my replies are wordy. An affliction of which I have not cured myself.
Quote:
Secondly I was attempting not to be prescriptive as I was looking for other opinion which may or may not coincide with my own.
As per our PMs even from the previous thread I appreciate you posting this thread and never took your words as prescriptive. My responses were to let some real visible examples do a little MythBusting rather than just supply opinion.
Quote:
So the points I set out to try and clarify were:
  • Any real benefit taking an 8 bit file and editing in 16 bit workspace and potential pitfalls. Some ‘gotchas’ I was already aware of and which you have highlighted in your replies.
I think that one was beat to death for this thread (I think). Visible degradation in some images in some common circumstances and not visible in many more images (IMHO)
Quote:
  • Is it possible that 8 bit to 16 bit could degrade image due to moving to the higher bit depth. This thought stemmed from a conversation with another PS user who was quite adamant that due to losing so many levels there were huge gaps in the histogram and these were not evident in the PS histogram views.
Yes and No

The conversation with the other PS user sounds like more of a misunderstanding of 16bit mode and associated 16 bit math used by PS. Hard to know without participation by that person. I personally don't know any case where using a higher precision data and math (16 bit mode) in Photoshop creates a worse result. I will leave that to someone posting an example.

That said, there is a case of cumulative degradation (added noise) when making round trips to 16 bit mode (not 16 bit mode created yet from the conversion). That is when the Dither Mode is check on in Color Settings. Every time you return from 16 bit mode back into 8 bit mode with Dither turned on, Photoshop adds random dither noise into 0.5% of your image pixels (Dither being 1 bit random variation per color channel). I confirmed this with an Adobe engineer and a documentation bug was logged. That noise is very difficult to see even with slowly changing gradients so is mosly an academic example. It would require many round trips to 16 bit and back for this noise to accumulate and be noticeable and who does that?
Quote:

The tradeoffs with file size and processing speed are not a huge concern to me at least. .
For many it may not be an issue. The way I look at it is when the combination of File Size, number of Layers, number of History States are large enough you eventually run out of allocated PS memory and PS ends up using your scratch drive extensively with a large performance slowdown. Basically its the performance "wall." Running in 8 bit mode pushes out that wall by 2X in base pixel image size. If you are within 2X of that wall in 8 bit mode and switch to 16 bit mode, you will hit it. Happens to me all the time yet I often work with very large files.

Thanks again Tony for posting this thread.
Reply With Quote top
Reply

  RetouchPRO > Tools > Software


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Free RAW Images for practice amica999 Salon 12 09-05-2017 04:41 AM
Resizing images for RetouchPRO jeaniesa Photo Retouching 19 11-05-2016 09:28 PM
A few images from the last roll of KODACHROME creativeretouch Photography 7 01-07-2011 09:27 PM
8/16 bit images! What's the difference ! john_opitz Photo Restoration 15 01-13-2005 05:10 AM
High Bit Scanning? Doug Nelson Input/Output/Workflow 1 08-18-2001 03:06 PM


All times are GMT -6. The time now is 09:16 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
SEO by vBSEO ©2011, Crawlability, Inc.
Copyright © 2016 Doug Nelson. All Rights Reserved