Precise Color Matching in a Graphics File

[sm4him]

This is not about a photo, but I guess it's the same principle.

We have a large sign in the lobby at my workplace that has to be redone, from scratch, because the company that originally did it evidently no longer has any of the files.

The problem is that I need to match the colors of the original sign as closely as I possibly can, because there are other signs in the area that are the same color scheme.

The sign has our logo on it, so that seems like a good place to start, because I know what the Pantone color of the logo should be.

I took a photo of the sign; of course, in the photo the logo isn't quite the right color--which I presume means the rest of the colors are off as well.

Can anyone walk me through how to adjust the colors on my photo of the sign, using the correct Pantone logo color as my starting point, so that the resulting photo is a fairly accurate representation of what the colors on the sign SHOULD be when I recreate it?

I'm working on the photo color correction in PS, but plan to create the sign in Illustrator, if that matters to anyone.

Here's the photo of the sign; the color of the logo SHOULD be PMS 382.

 

[Buckster]

This may be helpful to you:

Pantone color Coated 382 C to RGB Hex RAL HSL HSV HSB JSON

 

[sm4him]

I know the RGB, etc "equivalents" of that specific Pantone color, but no--what I want is a way to use what the correct Pantone color should be VERSUS what it actually is, in order to adjust the colors for the entire photograph, so that then I can use the colors for the other areas of the photo to determine my Pantone colors in the Illustrator file.

In other words, I guess I kinda want to correct the wb--but instead of picking a point that should be white, black or gray, I want to pick the point (the logo) that should be Pantone 382 and then have the whole photo adjust accordingly.

According to PS, the color that should be 382 is currently displaying as 374.

 

[Ysarex]

You can force a specific color in Photoshop using Curves but it won't do what you want and bring the rest of the colors in the photo around to correct values. Nice idea but I don't think it's possible.

The sign is still in the lobby I assume. You need one of these: ColorMunki Photo Software and Hardware solution X-Rite ColorMunki Photo

You should be able to rent one. It has an option to read specific color values from reflected source material. You can take it and directly read the color values you need right off the sign.

Joe

 

[runnah]

I would use a swatch book.

Looks like Pantone solid coated.

 

[Buckster]

I know the RGB, etc "equivalents" of that specific Pantone color, but no--what I want is a way to use what the correct Pantone color should be VERSUS what it actually is, in order to adjust the colors for the entire photograph, so that then I can use the colors for the other areas of the photo to determine my Pantone colors in the Illustrator file.

In other words, I guess I kinda want to correct the wb--but instead of picking a point that should be white, black or gray, I want to pick the point (the logo) that should be Pantone 382 and then have the whole photo adjust accordingly.

According to PS, the color that should be 382 is currently displaying as 374.

I get that you're trying to sample the known color in order to determine the unknown colors, but the colors, hues and luminosity levels aren't consistent throughout the photo of the sign as it is, so how would you be able to sample and get the rest of the colors to fall in line in any case? If you eyedropper the known green color all over the sign, it changes from place to place.

Maybe you could shoot it with a Color Checker target in the shot, and color balance off that to get a faithful reproduction of the colors used? I think you'd still need to get the light for the shot just right so that it's consistent throughout.

 

[photoguy99]

I think a color balance layer and some tinkering is what you want.

Be attentive to the red, green, and blue values separately. When you do match the logo's pantone color, though, I bet you everything else looks like garbage.

I'd just use the sign as a design reference and do the colors from scratch. Use a color managed workflow and print a scratch print to see if it looks well on site. Adjust as needed.

Then when your vendor takes your correctly profiled file and botches the sign anyways, burn their factory down.

 

[sm4him]

I know the RGB, etc "equivalents" of that specific Pantone color, but no--what I want is a way to use what the correct Pantone color should be VERSUS what it actually is, in order to adjust the colors for the entire photograph, so that then I can use the colors for the other areas of the photo to determine my Pantone colors in the Illustrator file.

In other words, I guess I kinda want to correct the wb--but instead of picking a point that should be white, black or gray, I want to pick the point (the logo) that should be Pantone 382 and then have the whole photo adjust accordingly.

According to PS, the color that should be 382 is currently displaying as 374.

I get that you're trying to sample the known color in order to determine the unknown colors, but the colors, hues and luminosity levels aren't consistent throughout the photo of the sign as it is, so how would you be able to sample and get the rest of the colors to fall in line in any case? If you eyedropper the known green color all over the sign, it changes from place to place.

Maybe you could shoot it with a Color Checker target in the shot, and color balance off that to get a faithful reproduction of the colors used? I think you'd still need to get the light for the shot just right so that it's consistent throughout.

I think a color balance layer and some tinkering is what you want.

Be attentive to the red, green, and blue values separately. When you do match the logo's pantone color, though, I bet you everything else looks like garbage.

I'd just use the sign as a design reference and do the colors from scratch. Use a color managed workflow and print a scratch print to see if it looks well on site. Adjust as needed.

Then when your vendor takes your correctly profiled file and botches the sign anyways, burn their factory down.

Yep, I think you're both essentially right; it's not really possible to do what I'd like, at least not without a lot more time and effort than it's worth.

I just thought I'd ask the question, really, in case someone else DID happen to know a way to do this.

I've done this "hey can you just recreate this sign" song and dance before, so winging it is something I *can* do, I just suddenly thought, "hey, maybe someone knows a way to make this easy!"

 

[sm4him]

You can force a specific color in Photoshop using Curves but it won't do what you want and bring the rest of the colors in the photo around to correct values. Nice idea but I don't think it's possible.

The sign is still in the lobby I assume. You need one of these: ColorMunki Photo Software and Hardware solution X-Rite ColorMunki Photo

You should be able to rent one. It has an option to read specific color values from reflected source material. You can take it and directly read the color values you need right off the sign.

Joe

Now THAT might be EXACTLY what I need! Maybe I'll look into what it would cost to rent one--and how long it would take to get it--but my guess is that my workplace won't want to spend the money, so I guess I'll just be doing the "close enough for government work" routine again. And since I technically work for the government, I mean that quite literally!

 

[photoguy99]

The thing is that you can get the color absolutely spot on and then some crazy property of the dyes or plastic under the ambient light can botch it all up in the end anyways.

Color matching is a thankless job.

 

[sm4him]

The thing is that you can get the color absolutely spot on and then some crazy property of the dyes or plastic under the ambient light can botch it all up in the end anyways.

Color matching is a thankless job.

Well, in fact, it's NOT going to be exact, because the finish is going to be different. The existing sign almost seems to have this micro-thin film with a satin finish over it. We're going to be having the sign printed on different material and just mounted to the same surface, so it WILL look a little different, and that will just have to be okay.

Still, the guy who prints this stuff for me is about as good as they get. I have absolute confidence that he will get it as close as possible. He'll be over tomorrow or Friday to look at it, and will take into account the ambient light and all that when he chooses the material and inks for the job. I've never gotten anything from him that I was disappointed in.

 

[photoguy99]

Sounds like you're in good hands! A vendor that will come out and look at the scene is probably the most important thing!

 

[epatsellis]

Shooting color accurate images has become significantly easier with digital vs. transparency film ( like we used to do in the old days).


Google Kodak Q13. Getting one is the first step.

The process is fairly simple, but time consuming. ( he says jokingly...)

Create a profile using the exact body, lens, iso setting, light source and aperture you will be using.

Illuminate the subject evenly, within a 1/10th of a stop.

Meter using an incident light meter.

Shoot the subject, having a Q13 chart at the edge of the frame.

Open the image and verify the Q13 patches are within tolerances of their reference values. If not, you can adjust the curves to get there if you're only a few points off, though I tend to edit color critical images in Lab color space personally.

The upfront work is time consuming, I have a dedicated body and lens just for shooting this type of work ( a Kodak SLR/n with a 55 f3.5 micro Nikkor). For art repro work I use something a little different (Betterlight scan back), but the same principles apply.

This is great for shooting product or art repro, but for what you want(ed) to do, another poster had it right, a PMS swatch book is the ideal reference.


Erie Patsellis


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