Is there an easy way to match local color in CS5?

[emil_ems5]

<p>I sometimes have to match the color in local parts of two pictures that will hang together on the wall. For instance, the grass on a football field. I seem to have problems with doing that in an easy way. The method I am applying at the moment is to take a small patch of (for instance grass) on each picture, average out the color there and manually adjusting one patch with curves to match the (average) color of the other.</p>

<p>But what I would love to do is simply to read the RGB values of the one patch and dial in those values for the patch in the other picture. Is there a way of doing this?</p>

[Matt Laur]

<p>In practical terms, is the problem a mis-match in the white balance (the color temps) of the images ... or simply that it's two completely different images shot when the grass looked different, and you want to artificially make up for that natural difference? The WB issue is pretty easy, across multiple shots. The different actual <em>content</em> issue is trickier, and eyeballing the mach with hue/saturation changes is probably easiest.</p>

[emil_ems5]

<p>Thanks Matt, for your quick reply. My question relates to the more general problem of matching two local areas in two different prints. Each print has overall the right white balance in place. </p>

<p>My concrete problem is about two players on a football field taken from different angles. With the sun shining from different angles, the grass color differs. I am eyeballing this, as you suggested in your response, but am looking for an easier way. It is quickly done in Photoshop to establish the RGB values for each of the two patches, but I find it rather cumbersome to adjust those values in one picture to those of the other, using curves. I was looking for a feature (that may not exist in Photoshop) where I could simply dial in the RGB values from on patch onto the patch in the other picture.</p>

[tom_mann1]

<p>In Photoshop, under Image / Adjustments, there is the "Match Color" tool. Sometimes it gets the colors a bit closer, but, in my experience, most of the time, it only provides a somewhat interesting variant of the original.</p>

<p>There is a very interesting, sophisticated commercial gradient-mapping plug-in called, "Foks Marx" (www.foksmarx.com) that can do "match color" tasks. It is much more difficult to use than the one built-in to Photoshop, but I found it doesn't really do better than "Match Color", at least for this relatively unskilled user.</p>

<p>As suggested by Matt, eyeballing it using hue-sat, curves, or similar techniques is often the best way.</p>

<p>Good luck,</p>

<p>Tom M</p>

[tom_mann1]

<p>BTW, I don't know how this slipped my mind, but I forgot to mention Color Mechanic, my old reliable color tweaking plugin ( http://dl-c.com/content/view/16/30/ ). It is very good at these sorts of problems. Why don't you post a couple of images that need to be matched and I'll see what I can do using Color Mechanic.</p>

<p>Regards,</p>

<p>Tom M</p>

[tom_mann1]

<p>Emil, this should give you an idea of what Color Mechanic can do to match grassy areas. First, the original with the grass in the upper part of the frame sunlit, while the grass in the lower part is not directly illuminated by the sun.</p><div></div>

[tom_mann1]

<p>... and here is the result of adjusting the color of the grass in the upper part of the frame to match that in the lower part of the frame.</p>

<p>There are some very important subtleties in using Color Mechanic to do this, but the entire fix probably took me well under a minute. If I hadn't rushed through the process, it would have come out even better. If you are interested in this approach, let me know and I'll be happy to describe my procedure in more detail.</p>

<p>Tom M</p>

<p>PS - Obviously, there are a huge number of other ways to accomplish the same thing instead of using Color Mechanic (and they will likely be suggested by future responders in this thread). However, IMHO, once you are familiar with this software, it's faster and easier than any of the other techniques. </p><div></div>

[JeffOwen]

<p>As Tom's example shows grass colour can vary enormously. I can't help you in solving your problem but I am fascinated in how part of a scene can be altered without changing the overall balance.<br>

Most people's recollection of grass colour is vivid green where as in actuality it can be anything from brown to blue, it has always been a great problem to film manufacture's and processing houses to satisfy customer's needs when it comes to colour matching. I wish you luck in your quest.</p>

[emil_ems5]

<p>Tom,<br>

Thank you kindly for your suggestion of Color Mechanic and going to the trouble of showing me an example.</p>

<p>I just have a follow-up question to your suggestion. Does Color Mechanic provide an easy way to pinpoint the RGB values in one region and replicate those exact values in a region in another picture?</p>

[tom_mann1]

<p>EE: <em>"...Does Color Mechanic provide an easy way to pinpoint the RGB values in one region and replicate those exact values in a region in another picture?..."</em></p>

<p>Yes. You click on the "Opt" (options) button on the LHS of the GUI and you are offered the choice of saving the current transformation, loading a previously saved transformation, or recalling the last used transformation. </p>

<p>As an example, attached to the next post is the graphical representation of the settings used to (a) darken and saturate the cyan sky, (b) clean up the white of the platform, and © make the rust more vivid in the attached pair of images. I picked this as an example (ie, instead re-using the grass example) because the changes were more drastic and easier to see.</p>

<p>HTH,</p>

<p>Tom M</p>

<p>PS - BTW, Color Mechanic has worked flawlessly from CS3 days to the present CS6. It works with both 8 and 16 bpc bit depth images. </p>

<p>PS #2 - I have absolutely no affiliation with the company that makes Color Mech. But, FWIW, it is especially useful to tame massive cases of acne and rosacea without destroying skin texture.</p><div></div>

[tom_mann1]

<p>...and here is what you would have had to do to achieve this.</p>

 

[tom_mann1]

<p>...argh... I forgot that photo.net doesn't display png's in-line. Here it is again -- this time as a jpg.</p><div></div>