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Setting- White and Blackpointand & other Questions

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  #1  
Old 09-13-2008, 10:54 AM
sirespen sirespen is offline
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Setting- White and Blackpoint & other Questions

Hello guys!

Yesterday I watched this: Color Correction with Taz Tally and this: Beyond Skin going deeper with Photoshop CS3.

The approach in both video is to adjust the colour and contrast before start with any retouching techniques. In every image the tutor first fixes the white point, the black point and adjust the colour. But what should I do if there isn't any? For example when I would have only a face where I haven't something that i can define as white point?

I also have this other image also from a thread here in the forum... The problem is that the sofa reflects some red light and on his back the jacket becomes more blue. Should I use the measure point in the middle of the other two to adjust the colour?

Do you do contrast and colour in 2 different curve layers or all with one?

I have also another concern...Why should anyone use Adobe RGB? I don't get it... I understand that it's a bigger colour space, but what advantage do I have? CMYK is smaller gamut so probably I haven't any advantage...

I hope I'm not stressing to much, but on this few question's I haven't found any satisfying answer :/

And sry for the bad English, I've read the thread a few times, but probably it`s full of mistakes...

Thank you in advantage! Have a good weekend!
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File Type: jpg domanda.jpg (82.8 KB, 47 views)
File Type: jpg domanda2.jpg (91.1 KB, 39 views)

Last edited by sirespen; 09-14-2008 at 12:42 PM.
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  #2  
Old 09-13-2008, 03:30 PM
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0lBaldy 0lBaldy is offline
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Re: Setting- White and Blackpointand & other Quest

I made this little action to help me find the Gray, White, Black points using a 50% Gray layer, Threshold then Levels to help me get a starting point..

~~I have changed the Action to one that is a bit easier and more understandable~~ (this is the first attempt at an action so please be understanding)
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File Type: jpg correction.jpg (190.7 KB, 78 views)
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File Type: zip Color Correct 2.zip (1.2 KB, 15 views)

Last edited by 0lBaldy; 09-14-2008 at 05:25 PM. Reason: Changed zip file to one more understandable
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  #3  
Old 09-13-2008, 04:41 PM
sirespen sirespen is offline
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Re: Setting- White and Blackpointand & other Quest

Thank you for your post. I think you have misunderstood my question... I don't want to define the skin as whitepoint. Correct me if I'm wrong, but I have the impression your action is useless. You cant set the whitepoint on her skin...Now she has Cyan coloured skin...

I hope someone can help me! Thank you!
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Old 09-13-2008, 05:39 PM
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0lBaldy 0lBaldy is offline
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Re: Setting- White and Blackpointand & other Quest

Yes, you are right.. your question is more technically advanced than my knowledge.. I have nothing of use to offer you..

Sorry.. I hope you find an answer to your problem from another user in the RetouchPRO Forum
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  #5  
Old 09-13-2008, 05:47 PM
sirespen sirespen is offline
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Re: Setting- White and Blackpointand & other Quest

No problem, thanks anyway

I'm sure someone will help me
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  #6  
Old 09-13-2008, 08:58 PM
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Verywierd Verywierd is offline
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Re: Setting- White and Blackpointand & other Quest

sirespen:

Accurately setting the black, grey and white points is important because it ensures that colour tones are consistent from one image to another, and provide a standard starting point from which you can fine tune your image. Have a look at this example, which also answers your question about what to do if there is no white in your image:

http://bermangraphics.com/digital-ju...hite-color.htm

I think that you have misunderstood what OlBaldy's action does. It does not set the skin as the white point. What is does is set the three points using an external reference just as in the example above. It is not "useless" but it is also not a magic fix. What it does is removes any colour cast from the image. Then you can decide if you want to make the image "warmer" or "cooler" (very generally, more yellow or blue respectively). If you don't set the points first, your image will most likely already have a colour/temperature bias, which will then mix with any adjustments that you make and give unpredictable results.

In your second example, the shades of blue and pink are irrelevant with regard to white point, as there are plently of areas in the image that you logically know are white. You only pick a non-white point if you know that the area should be white (but isn't white in the picture).

To take an extreme example, suppose you take a photo with a pure white paper background. However, by accident you leave a blue gel on your light source, or you set your digital camera white balance to "tungsten". When you look at you picture, you will see that your background is bluish (as well as everything else). You might even like the result. But the point is, you did not start out to deliberatly get a blue picture. So, if you pick your bluish background as the sample "white point", Photoshop will bring your picture back to "normal" and remove the accidental blue. (Note that the grey point is important for this purpose too). You will now have a white background and the skin of your model will look like it does in real life under neutral lighting. NOW you can look at the picture and say "Hey, she looks too pale", or "Hey, I want to make her look like those fashion shots with greyish skin." and adjust accordingly because that is what you want, and not because of an off colour light source or expired roll of film.

Adobe RGB is a whole different subject which I will leave to someone else.
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Old 09-13-2008, 09:29 PM
duwayne duwayne is offline
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Re: Setting- White and Blackpointand & other Quest

I've had the same problem so yesterday ordered one of these. It seem like it might solve the white balance and neutral issue when you don't have a true white in the image.

http://www.rawworkflow.com/products/whibal/index.html
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Old 09-13-2008, 09:37 PM
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TommyO TommyO is offline
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Re: Setting- White and Blackpointand & other Quest

Sirespen,
A very brief review...

Yes, correct tone, contrast and color first.

Set black/gray/white points to improve tone, contrast, correct exposure and correct color casts when present. Use separate adjustment layers for each and label them properly so you can tell which is which later.

If your image does not have exposure problems, and does not contain true whites or blacks, then you should not use the black and white point eyedroppers. Correct the colors by the numbers.

In your second image, you will have to use the mask. Paint white to reveal the correction only where needed. You will need more than one layer, separating the correction for the red and blue color casts.

Use a broader color space (Adobe RGB or ProPhoto) in order to retain the colors for your original image and of course for future technologies that can use them. It also prevents destructive edits from removing as much color data - a smaller space will begin to reveal problems faster after a lot of editing. CMYK also results in bigger files; not too important unless your files are very large, i.e. a 1 GB RGB image will be about 1.3 GB in CMYK. You may not be able to print all those colors. But, you can see the end result and make corrections during soft proofing. Then make your final edits and convert the image to your printer profile before sending off. They should match.

Your English is pretty good. However, thank us in advance, not advantage !
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  #9  
Old 09-14-2008, 03:30 AM
sirespen sirespen is offline
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Re: Setting- White and Blackpointand & other Quest

Hey! Thank you very much for your answers!
OK, I've understand the main procedure and was the action from Obaldy (sry Oblady for my ignorance) does.

But suppose that you have a photo there you can see only skin, so there isn't any neutral colour. You have to correct it by Numbers. But what about luminosity? I learned that the whitest relevant point should be 245/245/245 and the darkest relevant point 10/10/10 to preserve details.
OK, but when I have plain skin, I'll have only mid tones. How can I assure that is not to dark or to bright (by Numbers, )? Probably it's a matter of taste, because in the mid tones we haven't the problem that something is blow out. But suppose I have to adjust it so, that's it's perfectly lit, like I would have put (?) a grey card in front and set the mid tones to 128 ecc.

Is that possible without a grey card?

Thank you in advance :P
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  #10  
Old 09-14-2008, 06:16 AM
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Verywierd Verywierd is offline
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Re: Setting- White and Blackpointand & other Quest

When you can't find a neutral (grey) spot you can try this plugin:

CSpringer_sDigitalGreyCardCS3

which you can download from

http://www.freewebs.com/fairyfuntuto...hopactions.htm

There is an explanation on how it works on the page.
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