A colour matching issue.

[dypinc]

I've been playing around with a developing a web app to help with spot color matching. I'd be interested to see if it's helpful for you or others
http://spotcolormatch.com

Might be a lilttle flaky while I work some issues out, but it's free...

Thanks,
Mike

Spot color matching really needs to be done at the RIP output level. If your using CMYK or RGB then the RIP input level is being used. Turning color management off is not a good option either because you then loose consistency with multiple colors.

Your app might be useful for those not using proper color management or low end RIPs not capable of using LAB values in a spot color table correctly.

Matching spot colors correctly, within a normal workflow involves proper color management to determined total or max gamut of your output device. A RIP then should be able to look up the spot color from a library and print that color as close as possible within the gamut limitations of that device. If you have many spot colors in a document all of them will then be as accurate as possible. Any adjustment of colors should be done at the library level (or make a new library) by adjusting the LAB values which can easily be done by reading the value in with a Photospectrometer off of a Pantone book, vinyl or even a paint chip.

 

[mikeinpdx]

True, there is the best theoretical way of doing things, and then there is "what is the quickest way of getting this done that will make the customer happy that I can do and afford" I've got a spectrometer, gone that route, but in practice for me the combinations of media/laminate/profiles usually meant I took that Lab reading to get close, and then printed/lam a range of samples around it, since I didn't have time and couldn't afford to have someone come in and profile the various media/laminate combos (in other words, I didn't see the return on investment, even if I could afford it).

Most of the time, customers I have don't really care about color as long as it "looks good" - UNLESS they were picky about a few spot colors being hit. So I'd print/lam a color chip set and let them pick. I was using some utilities I found useful to do that, then just decided to put it in an app and see if it had broader use to others. It was a way to make my job easier -- let the customer pick the best match. Which sometimes isn't even the closest one.

The simple "print samples and narrow down to the best one approach" works for me, even though I realize that probably makes color management experts shake their heads in disdain. Typically, I might only have 3 or 4 spot colors to hit. If there were dozens to hit, true, a much more robust color management approach would be the way to go.

Spot color matching really needs to be done at the RIP output level. If your using CMYK or RGB then the RIP input level is being used. Turning color management off is not a good option either because you then loose consistency with multiple colors.

Your app might be useful for those not using proper color management or low end RIPs not capable of using LAB values in a spot color table correctly.

Matching spot colors correctly, within a normal workflow involves proper color management to determined total or max gamut of your output device. A RIP then should be able to look up the spot color from a library and print that color as close as possible within the gamut limitations of that device. If you have many spot colors in a document all of them will then be as accurate as possible. Any adjustment of colors should be done at the library level (or make a new library) by adjusting the LAB values which can easily be done by reading the value in with a Photospectrometer of a Pantone book, vinyl or even a paint chip.

 

[derekw13029]

We do a lot of fine art reproductions and giclee's.

Since we either have to scan the art (usually paintings) or if they are really, really large we send them off to a nice studio to be shot, there is A LOT of color matching to do with those files.

Trying to match every single stroke of color can be a pain.

From what I understand, most of you are saying you should only be using your RIP for color matching? To me, that's absurd. I have to meticulously use photoshop to alter the image (sometimes significantly) to match the actual art. If someone brings a photograph or a graphic, it's a whole different situation.

But I don't see any way you could do any kind of fine art reproduction without using Photoshop to alter the colors, print a proof, see how it looks, and adjust as needed. I don't trust any of my equipment enough to know exactly what something will look like, especially after something has been scanned or shot.

 

[dypinc]

We do a lot of fine art reproductions and giclee's.

Since we either have to scan the art (usually paintings) or if they are really, really large we send them off to a nice studio to be shot, there is A LOT of color matching to do with those files.

Trying to match every single stroke of color can be a pain.

From what I understand, most of you are saying you should only be using your RIP for color matching? To me, that's absurd. I have to meticulously use photoshop to alter the image (sometimes significantly) to match the actual art. If someone brings a photograph or a graphic, it's a whole different situation.

But I don't see any way you could do any kind of fine art reproduction without using Photoshop to alter the colors, print a proof, see how it looks, and adjust as needed. I don't trust any of my equipment enough to know exactly what something will look like, especially after something has been scanned or shot.

This thread is about matching spot color or spot created from any measurable solid color. Not sure where you got that this had anything to do with halftone images.

I have printed fine art reproduction for years and you are right, all adjustments should be done with Photoshop. In this case the printer should be calibrated with the RIP or onboard and then a profile should made for with or for the RIP. No adjustment should be made at the RIP level other than rendering intents. Although if EVERYTHING is properly calibrated and profiled what you see on the monitor should be pretty damn close to what it looks like when printed.

Specifically what I was talking was adjusting the LAB values of colors in Spot Color Libraries which if needed should only have to be done once, and best done by reading in those values with a photospectrometer.

 

[Z SIGNS]

We don't play the color match game

Color matching is a PIA and subjective.

I feel sorry for those that have to make a living dealing with the customer that wants to talk about the 256000 shades of whatever.

The only way around the problem is to only print what you design then the colors are never off.

Good luck with your replications

 

[Andy_warp]

Pure hues

What RIP are you using? Some of them have the ability to only print pure hues, negating additional channels from the build which can muddy up a yellow in a heartbeat. The problem I have with most of these posts, is that all cmyk inks are different. I cringe when I see a "simple" solution of someone throwing an arbitrary build out as a solution. I also hate to see the whole "color management is evil" approach. It's ludicrous to believe winging it is a better solution than using the devices and software technology has provided us.

That's great to know your printer well enough to do that...but what happens if you upgrade printer/ink/rip?

Color management is not buying an i1 and scanning some swatches to hit a yellow. It's creating an environment that will produce REPEATABLE results.

Without having an idea of your maximum print gamut, it's hard to know if you can hit a color using only your 4 channels.

In the most refined managed color workflow, there are spot colors still unattainable. This sounds more like a customer education issue, as they don't teach this in art school.