Apply color variation calculated from target and source image

[jozemaner]

Hi! I'm new here .
I was wondering... does anybody knows a way to, have a source color chart, a target color chart, calculate what are the variations between them, and then use that to apply it to another image?
I'm not talking about "match color", I know how that works, but is not what I'm looking for.
It can be compared to switching to a custom color profile (calculated by the variation of source and target). Or something like "color lookup" (but with a custom icc/icm/lut).
Creating a custom icc has been really complicated for me, and I still can't get it to work. (I have the icc profile, but can't open it nor from "convert profile" nor from "color lookup").
Any other ideas? I can't be the only one searching for this...
Thank you!

 

[Tom Mann]

There are two previous threads on this forum that dealt with similar questions, and may be of interest to you:

http://www.photoshopgurus.com/forum...changes-copy-original-image-another-copy.html

http://www.photoshopgurus.com/forum/general-photoshop-board/42165-color-matching.html


Realize, of course, that what you are asking for is difficult, and, in fact, may not even have any solution.

For example, consider the case where the colors and tonalities in image 1 are transformed by some procedures into image 2, you are only given the two images, and then asked to find a set of rules that could be used for other images of the same general type.

Well, a red in the upper LH corner of image 1 may be transformed into a lighter red in image 2, but the exact same red in the lower RH corner of image 1 may be transformed into a darker red in that location. So, there is no single / unique rule telling one how to transform reds in that image. Of course, this is a simple example, and one could imagine work-arounds for this. However, much more complicated transformations are also possible that couldn't be so easily dealt with.

HTH,

Tom M

 

[jozemaner]

Thanks for the answer! Yes, you made your point. And yes, I was thinking in something like "all the colors similar to this one, will be transformed to this one", and if there is more than one transformation, a mix of them. But actually, those links are really helpfull. I guess there is no automatic way to do this today. Maybe in the future . Thank you very much!

 

[Tom Mann]

I'm glad to have helped. The question that you posed is extremely interesting. A solution to it, even if only for a restricted set of circumstances could be useful in many real world situations. I suspect that there may be papers on such partial solutions in the image processing academic / research literature. If I get a chance I'll take a look.

If you find anything, come back and let us know by posting in this thread.

Best regards,

Tom M

 

[jozemaner]

I actually got into something that "should have worked"... but it didn't (it make sense, because is a really alternative way of achieving it, with many flaws).

1) You have a color table (something like this http://ecx.images-amazon.com/images/I/61teZBiWnlL._SL1400_.jpg). This will be the "input color table"
2) You process it (this could actually be taking a photo of it with another camera). This will be the output color table"
3) You use a software (lprof in this case) to calculate the icc calibration between those input and output.
4) What you have is an icc that does exactly the OPOSSITE of what you want hahaha. This is because is for calibration. What is does, is a correction of your "process". Is to calibrate scanners, cameras, etc.
5) So, you process the input color table with this icc, and you obtain the "contrary output color table". You use this one as the new "output" that you want to achieve. The input is still the input color table.
6) Now it generates a new icc that "should" do what you want.
But the process is so complicated and has so many flaws (for example, input color table should be what your camera see, not a perfect color table) that the results are horrible. (I don't have them with me right now, but trust me, they stink).
We will have to wait for an image processing software to do this, I guess.. ¬¬
That's my approach.
Thanks for the reply again! Will come back if I have any news!

 

[SCTRWD]

I'm afraid I do not understand it clear but what is wrong with simple color tables?

Make color table from the source color chart, make the color table from the target color chart.

To make a color table from a color chart do the following:

1. Make your chart 16x16 pixels.
2. Save it as RAW file with Interleaved Order.
3. Find your file on disk and change it's extension to ACT.

Then for any image convert it to source color table and then change the color table to target color table.

Isn't that what you want?

 

[jozemaner]

Hi. Thanks for the answer.
I want to try that. I don't actually get it... can you be a little more specific with the steps?

- Does this procedure will allow me to change a whole photo from one "general color look", to another?
- Each pixel is a different color in the color table? So I should have 16x16 = 256 colors?
- Do I save it directly from photoshop as a Raw file? What extension?
- For converting, I should use "convert to profile" in photoshop?
- To change to the target color table? Assing profile?
- If, for example, I want to make the variation from one digital camera to a vintage camera... I create a 16x16 color table, I take a photo of it with the digital camera, and then with the vintage camera. With the first file I create the first act, and with the second, the second act. Then I convert any photo from the digital camera to the first act, and then I assign it to the second act? Is this correct?

Thank you for your answer! This is getting interesting...

 

[jozemaner]

Sorry, I don't get this. Act? How do you install the color table in photoshop so that you can use it to convert an image to it?
Thanks!

I'm afraid I do not understand it clear but what is wrong with simple color tables?

Make color table from the source color chart, make the color table from the target color chart.

To make a color table from a color chart do the following:

1. Make your chart 16x16 pixels.
2. Save it as RAW file with Interleaved Order.
3. Find your file on disk and change it's extension to ACT.

Then for any image convert it to source color table and then change the color table to target color table.

Isn't that what you want?

 

[jozemaner]

Oh, I get it. I think we are talking of different things. The image is not under a color table (like a gif, or something like that). I'm talking of an actual 16-bit image. What I want is not to change colors of the color table of an image. I want to apply color variations to a photo, taking in consideration 2 color profiles (Is an interpolation of color process). Maybe that's what you were talking about?

 

[SCTRWD]

Sorry for not answering for so long, I was out of state.

Apparently I was misled because you talked about color tables in your recent post...

What I was talking about is that for Index color you can make color table file just by making 16x16 image with each pixel representing the color of your color table. Then by following the described process you can get a color table file.

Color table file is nothing more but 256 byte triples:
R1,G1,B1,R2,B2,G2, .... R256, G256, B256

Make the color table file for source color chart, then make the color table file for target color chart. And then you can turn any image to Index color with source color table and change it's color table to target color table thus effectively changing the colors the way you wanted

That can solve the issue but via Index color mode. But now that you want it as a straight 16-bit image I don't really know how you can do this in a general case. Maybe messing up with icc color profiles would do you good. I tried it long time ago but to no avail:sad: