How to get "old colors" when moving to an ICC work

General Color & Graphics Printer Calibration & Profiling
1

What would you recommend in the following case:

We have previously printed to a DesignJet 1055 without any ICC workflow. Now, we’ve got a new DesignJet 5500 and want to move to an ICC workflow BUT want to preserve the colors as closely as possible as they printed from DJ 1055.

Of course, since there was no ICC workflow in place, just calibrating the monitor and profiling the printer won’t give us the “old colors” because the “old colors” where probably “wrong”. The purpose is map printing so the number of distinct colors is fairly small. Can we do something like measuring colors from old prints and input them as sRGB values to our application, giving us the old colors with their real sRGB values?

In other words, is there a cheap device that can measure colors from paper and give us sRGB values or some other values that can easily be converted into sRGB? Or is there some other way we should go?

We do not need “high-quality color matching”, just a reasonable match to old colors.

Thanks in advance!

Antti

2

At 8:31 AM -0700 8/6/05, nivant wrote:

What would you recommend in the following case:

We have previously printed to a DesignJet 1055 without any ICC workflow. Now, we’ve got a new DesignJet 5500 and want to move to an ICC workflow BUT want to preserve the colors as closely as possible as they printed from DJ 1055.

a variation on an old classic…

Of course, since there was no ICC workflow in place, just calibrating the monitor and profiling the printer won’t give us the “old colors” because the “old colors” where probably “wrong”. The purpose is map printing so the number of distinct colors is fairly small. Can we do something like measuring colors from old prints and input them as sRGB values to our application, giving us the old colors with their real sRGB values?

perhaps.

Here’s the situation.

  • First, I hope you still have the old printer.
  • If no color management occurred when printing to the 1055 then the files could be considered to be “in” “1055 CMYK”.
  • What are trying to do is print to “5500 CMYK”
  • In order to do this you need a profile for the 1055 and one for the 5500. Then you simply convert the files (In Photoshop or in-RIP or whatever) from 1055 to 5500 CMYK.

Make sense?

A curve ball would be if the files are in RGB. This is still possible though. What you do is print an RGB profiling target to the 1055 and build a profile of the “RGB print path” to the 1055. Then, as above, you would convert from the new RGB profile to the 5500 profile and you’re set.

Both of these conversions would involve first Assigning the profile in Photoshop and then Converting to the destination.

In other words, is there a cheap device that can measure colors from paper and give us sRGB values or some other values that can easily be converted into sRGB? Or is there some other way we should go?

not a cheap device but a fairly cheap service (our ColorValet service)

We do not need “high-quality color matching”, just a reasonable match to old colors.

yup, that should do it.

A variation on your story is one where a printer brought us a color copier print that their customer loved but they could not reproduce on press no matter how hard they tried. The customer liked the copier print so, effectively, their file was in “copier CMYK”. We built a profile for the customer’s copier and then converted the file from copierCMYK to SWOP-CMYK and they were set.

I remember them saying they could have never done it with curves and that’s the truth. Color Management is WAY MORE than curve correction. It’s all about appearance matching. If you can capture something about the source appearance then you can usually convert to your destination and save hours of work.

Hope this helps…

Regards,

Steve

o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX

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3

Here’s another variation that has me a bit confused. A client supplies Proofs to us that he wants me to match on our proofer. There are a number of images embedded with USWebCoatedSWOP, many also with a SWOP Coated, 20% profile (which is different than the previous), and some untagged. Their proofs aren’t close enough to ours, but the client has seen and ok’d the supplied proofs.

Now, I can make a profile of their printer easy enough, but then I’m not sure how to implement it. Should I convert from the embedded profile to their printer profile, then to our custom profile? Or should I assign their printer profile, then convert to my profile? I’m thinking the latter as a softproof using the embedded (SWOP or SWOPish) profile doesn’t seem to match to well to their supplied proofs.

This isn’t much different than the scenario you described, but I guess I don’t know what, if any conversions are going on with the embedded SWOP profiles at the time of proofing. I suppose If the proof the profiling target in the same manner, that may cover the bases though.

4

Indeed, the files are in RGB. Sorry that I forgot to mention such a critical piece of information.

Another key point is that we are not using PhotoShop. The customer is using M-Color, which uses sRGB colors by default and converts them to device RGB with the help of an ICC profile, if available. Colors are going through the Windows printing system (which requires RGB) and PostScript cannot be used here, so CMYK is not an option here.

This case is not really about converting old images to a new RGB space but rather about adjusting the customer’s color palette, about 100 distinct colors defined in RGB, so that they print in the old way from their new 5500. At the same time, they want this color palette to be converted into sRGB so that they can easily print to other devices that produce reasonable output if the input colors are sRGB.

So, if I understood your suggestion properly, I should do the following:

  1. Print an RGB profiling target to the 1055 and get a printer profile for it from ColorValet.

  2. Using the profile, convert an RGB image of the color palette from “1055 RGB” to “sRGB”

=> I now have the color palette’s colors’ sRGB values, which fulfills one of my goals.

  1. Print an RGB profiling target to the 5500 and get a printer profile for it from ColorValet.

Now, the customer can use the sRGB colors of the color palette and print to the 5500 using the new profile, getting consistent output compared to the old 1055. Right?

Antti

5

I would say that ignoring the embedded profiles, assigning their printer profile and then converting to yours will probably get the results you want. I suppose I might be tempted to try it both ways just to see…

I find that embedded CMYK profiles get respected & used so rarely that it is almost always safe to assume that they get tossed and treat the files as untagged.

I’m interested to hear about your results though…

regards,

Steve

6

Yes, indeed, I think that’ll do it. The final step of creating an RGB profile of the 5500 is a good method to get RGB values for them to use in new documents…

An alternative that might be more flexible is to leave the values in sRGB and then get your 5500 printing sRGB values well. If you are driving it with a RIP you should be able to setup a queue with sRGB as the source for RGB data… now whether the RIP converts well and also converts all the forms of RGB well (like text, vector, etc) remains to be seen.

The sRGB route would be more flexible in the future as you will undoubtedly be changing printers / media / etc eventually and if they were using sRGB then they would not need to rework their files… the custom profile method would probably be the most accurate though. It gets the color conversion out of the RIP and into Photoshop where it is MUCH more likely to be correct.

please let us know how it goes!

regards,

Steve