RetouchPRO

Go Back   RetouchPRO > Tools > Vendor Support > Hidden Power Support
Register Blogs FAQ Site Nav Search Today's Posts Mark Forums Read


Hidden Power Support Support and discussion area for Richard Lynch's book and software series

Getting rid of background

Reply
 
Thread Tools
  #1  
Old 07-25-2003, 04:24 AM
Claude Claude is offline
Junior Member
 
Join Date: Mar 2003
Location: Belgium
Posts: 13
Getting rid of background

Hello,
It is a common problem in microphotography that the illumination of the microscope field is not completely uniform.
Question: would it be thinkable to take two photos, #1 of the empty field, #2 with the object and combine them in one psd as layers and substract #1 from #2 to get rid of the background?
Masking is out of the question due to the contorted character of the object and the unavoidable loss of edge detail in touching up the mask.
I hope I did not miss the obvious answer to this in Richard's book,wich I confess to be still digesting.
Reply With Quote top
  #2  
Old 07-25-2003, 06:39 PM
pmarchant pmarchant is offline
Member
 
Join Date: Jun 2003
Location: Reading, England
Posts: 30
Lightbulb Masking is the way to go...

... it's just how you create the mask.

Try this:
1. Start with two layers:
-- the bottom layer is your picture #2, label this 'image'
-- top layer is picture #1, label this 'bg'
2. duplicate the image layer and move it to the top, so that the layer stack is:
image copy
bg
image
3. with the 'image copy' layer selected, change the blend mode to "difference" and merge down (command/ctrl+E)
4. use the HP tools "Clear Black" and "Commit Transparency" and rename the resulting layer 'mask'

You'll find that the bg layer has now been replaced by the mask layer. To use the mask layer:
1. duplicate the image layer and move to the top.
2. group the 'image copy' layer with the mask layer (command/ctrl+G)
3. select the image layer and create a new fill layer

You'll find the background replaced by the fill layer's content.

Note this'll only work if the background you want to remove is the same in both pictures (so that the 'difference' in the RGB values is '0' and thus renders as black)

Cheers,
Paul.

Last edited by pmarchant; 07-25-2003 at 07:17 PM.
Reply With Quote top
  #3  
Old 07-25-2003, 08:59 PM
Richard_Lynch's Avatar
Richard_Lynch Richard_Lynch is offline
Senior Member
 
Join Date: Oct 2001
Location: Western NY
Posts: 1,105
Hmmm. Somebody's been studying their Hidden tools. Difference mode is indeed a good solution IF the lighting will be identical between shots and IF the object being introduced is not completely opaque in areas.

Nice solution Paul.
Reply With Quote top
  #4  
Old 07-26-2003, 10:02 AM
Claude Claude is offline
Junior Member
 
Join Date: Mar 2003
Location: Belgium
Posts: 13
Paul,

Thank you for a quick and very clear answer!
It works beautifully. one little point though: "Clear black" did'nt work but "Drop Black" did; Ctrl+E did'nt work but Ctrl+G did.
Any comments ?

Richard,

Thanks for dropping in. Both ifs are met
What part of your book should I have read more attentively?
Reply With Quote top
  #5  
Old 07-26-2003, 10:15 AM
Richard_Lynch's Avatar
Richard_Lynch Richard_Lynch is offline
Senior Member
 
Join Date: Oct 2001
Location: Western NY
Posts: 1,105
Quote:
What part of your book should I have read more attentively?
Well, I don't know that Paul's solution was something you'd get directly from readig the book unless you REALLY DIGESTED the whole thing. That is a combo of CMYK separation and layer masking...very much something he could have come up with based on those techniques, but I don't know that it isn't something else.

As far as the difference between drop and clear black...it sometimes depends on what you are doing, and I think either of these will work. You want to group with the mask and commit the transparency (so it is actually transparent rather than just invisible). If you aren't sure why you are doing either of these, I'd re-read those sections too.

I don't know that I said anything there...did it help?
Reply With Quote top
  #6  
Old 07-26-2003, 11:54 AM
Claude Claude is offline
Junior Member
 
Join Date: Mar 2003
Location: Belgium
Posts: 13
[QUOTE]...really digested..
I suspect that is still going to take some time
I recently got my hands on a copy of PS 6, so the temptation lurks to make the whole thing an action .

BUT the process uses your HPE1 tools...so the question becomes: can I just copy (or install..) them in the action directory of PS 6 ?

OR do I have to fish out the equivalent steps in PS 6 ?

OR can I access the HPE 1 action script (wich I surmise was written in PS x)and read off the PS steps ?

OR am I too ambitious ?
Reply With Quote top
  #7  
Old 07-26-2003, 02:26 PM
Richard_Lynch's Avatar
Richard_Lynch Richard_Lynch is offline
Senior Member
 
Join Date: Oct 2001
Location: Western NY
Posts: 1,105
these are good questions.

a) Can I copy? i don't know that there is anything you can do with actions in PS6 that you need my Hidden Power for. if so, and you need to use a reference, that is ok (this would say something like Play hidden power "this action" in the action steps). Copying the sequence to a new action is a copyright violation. Re-recording, technically is not. conceptually, I leave that up to you. If it is for only your use...the restrictions are far fewer.

b) You may simply need to learn to work with tools a little more in-depth to apply some of the background I have included in the tools, but i DO NOT discourage you from taking the tools apart and learning from them. In fact, the book tells you everything the tools do...my goal was to educate the reader, and the more you learn, the better!

c) am I too ambitious? No. You have the PS6 demo, PLEASE use it to your advantage. All I ask is that you don't do like some already have and run away with my idea claiming it is yours. I can't enforce, and won't. I'd just like to have my ideas help promote my book and free tools...and those that need help will hopefully come and use them. Hopefully everyone benefits. All I want is that I get proper credit for my ideas and effort.

I hope that answers. if you need to we can set up a call to discuss.
Reply With Quote top
  #8  
Old 07-26-2003, 02:29 PM
Richard_Lynch's Avatar
Richard_Lynch Richard_Lynch is offline
Senior Member
 
Join Date: Oct 2001
Location: Western NY
Posts: 1,105
Really Digesting

is going to take time. As i say in the intro...10+ years (now 11) and still learning every day. If you take photography before that there are a lot more years (started when I was 9). Can I fit it all in a 300 page book? Do I expect you'll grab every nuance that is clear to me?

You'll probably have to read it a few times at least!

Richard
Reply With Quote top
  #9  
Old 07-26-2003, 05:00 PM
Claude Claude is offline
Junior Member
 
Join Date: Mar 2003
Location: Belgium
Posts: 13
Quote:
i don't know that there is anything you can do with actions in PS6 that you need my Hidden Power for
Oh, but there is!

First it would allow to automate the elimination of the background in large series of micrographs and relieve the strain of watching my "steps"(pun intended)

Second, it would let me peek in the innards of actions and learn how they tick so that

Third, I could risk my hand at creating some, mail them to you and IF they are working well and IF you find them useful, I would be honoured to see them included in one of your future batches(does this settle the copyright infringement issue?)

Quote:
10+ years (now 11) and still learning
How boring are days without !

Thank you for your help
Reply With Quote top
  #10  
Old 07-26-2003, 10:34 PM
pmarchant pmarchant is offline
Member
 
Join Date: Jun 2003
Location: Reading, England
Posts: 30
Glad it worked in the end.

The difference between "clear black" and "drop black", is that clear only removes pure black, whereas drop additionally fades out the "almost pure" blacks. I suspect that your two images may have looked the same, but the underlying image data was just slightly different. In which case the difference blending won't yield pure black.

I don't know why Ctrl+E didn't work, as that is the keystroke for Layer>Merge Down which merges the currently selected layer with the layer immediately below (as long as both are visible).

I've only had Richard's book for about 3 months (and PSE2 for about 4) so I've not digested it all! I find I'm using masking a lot, and the excellent section on saturation masking demonstrates you don't have to use the lasso tool to create masks. Once you understand what the Transparent Blending HP Tools do, making masks gets easier. For example, by using a levels-corrected luminosity separation, a curve, and Transparent Grayscale I was able to create a midtones mask. With different curves I also got masks for shadows and highlights (but now HPT3 provides a quicker way to do these two).

It's also worth playing about with the blending modes. I just created black, 50% grey, and white fill layers, a black to white 0deg gradient layer, and a spectrum 90deg gradient layer. Then tried various combinations of the layers to see what (if any) effect the blending modes have.

Cheers,
Paul.

Last edited by pmarchant; 07-26-2003 at 10:43 PM.
Reply With Quote top
Reply

  RetouchPRO > Tools > Vendor Support > Hidden Power Support


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
uniform background and printing Angela9 Photo Restoration 15 05-02-2007 09:15 AM
How to replace a black background? buso23 Photo Restoration 6 01-16-2006 09:02 AM
Help needed with using light on background junipaire Photo-Based Art 3 04-15-2005 10:37 AM
Getting rid of background Shoff Image Help 12 10-25-2004 09:11 PM
Lily problem and solution p.156-157 dpnew Hidden Power Support 7 02-04-2004 12:01 PM


All times are GMT -6. The time now is 08:27 PM.


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