CHROMiX

ColorCast Proofing Profile

Following instructions in ColorThink Pro Video #4 at about 12 minutes, I used the ColorSmarts Guide with ColorCast to create GRACol proofing profile for proofing through ColorBurst RIP v7.3 to Epson SP4900 inkjet printer. I dragged GRACoL2006_Coated1v2.icc into “Proofing Profiles” area and then the standard proofing profile which we have used for many months into “Device Profile” area. The resulting profile which was made with a resolution of 33x33 was over 22mb in size. The RIP failed to print with it at first. But, after several attempts, the test finally printed. The result was highly over saturated, balance was off and midtones and shadows were much heavier than a normal proof. I uploaded the resulting ColorCast profile to you through the feedback area of ColorThink. Do you have any idea what may have gone wrong here? Thank you.

Hi Paul,

What you’re doing is making a ColorCast profile using two, large printer profiles. ColorCast puts the effect of one profile into the “guts” of another profile. So when the second is another complicated printer profile, and you use 33x33 grids, then the final profile will end up being very large. I guess it’s not surprising that a RIP will have trouble dealing with that.

[2] If your purpose is to proof GRACoL, then the ColorBurst RIP will do that for you already. In ColorBurst, you would take the standard profile for your 4900 and set it as your “CMYK profile”. Then you set GRACoL as your “Simulation” profile. ColorBurst will convert your images into the GRACoL color space, and then print it through the normal inkjet profile you have set up.

[3] If your purpose is to have a profile you can share with others so they can soft-proof without having a RIP, then that’s where ColorCast comes in handy. You would put GRACoL into the “Proofing Profile” area, and as we recommend: AdobeRGB in the “Device Profile” area. Then, you can take the resulting ColorCast profile and others can use it to soft-proof in Photoshop.

[4] If your purpose is to have a means of hard-proofing without a RIP and without Photoshop, then you would set up ColorCast with GRACoL as the proofing profile, and your inkjet profile as the device profile. The ColorCast module places the effect of the GRACoL profile in front of the inkjet profile, and the resulting profile can be placed in the print workflow wherever you would put the normal inkjet profile.

It sounds like what you’re attempting is closest to #4 above. If you tried it with a smaller grid choice your results will probably be better.

Hi Pat,

Thank you for this. Yes, I was aware of the simulation method in ColorBurst as well as the creation of a proofing profile described in paragraph 3. What I actually did is exactly what you describe in paragraph #4. Then I printed with the resulting profile through the ColorBurst RIP as an output profile. So, are you saying that if I had printed using the resulting ColorCast profile directly from PhotoShop or wherever rather than the RIP, then the results would mimic those obtained through the RIP as per your description in paragraph #2? As I mentioned, the results I have so far through the RIP are highly oversaturated.

By the way, the reason I selected 33x33 resolution is because that is what was used to generate the original printer profile in Monaco Profiler. If I select a lower res in Colorcast to generate profiles will there be any quality loss i.e. does it work in the same fashion as reduced image resolution? Thanks again,

Paul

Hi Pat,

Further to the above post, I subsequently made a ColorCast profile using the method you described in the 4th paragraph as before but with a resolution of 25 x 25. The resulting profile was about 1/3 the size at 7 mb. The ColorBurst RIP still failed to print again on the first attempt. But it was successful thereafter. However, the colour was the same result as before i.e. highly over-saturated and the balance was off.

Then I tried to print a proof directly from PhotoShop CS5 using the CC profile and it worked. The colour was also much closer to that which would be expected. However, there is an overall tint value starting in the whites - a light grey. The first few steps of the neutrals also show this in Profile Inspector. This is not how a print through the RIP would look. The profile and proof were made with the intent set to Rel Col. So, do you know what is causing this?

Thanks,

Paul

ColorCast profiles are intended to replace RIPs. I don’t know if I’ve ever tested one actually ON a RIP, but I can see where you want to use it this way in order to test it. The conversion through the CC profile needs to be the only conversion taking place, so you’d want to turn off any simulation, check to see that you’re not having the RIP convert from an RGB image to CMYK, etc. Look over your workflow very carefully to make sure no other conversion is taking place - or else go the Photoshop route.

The tint you are seeing is due to a bug in the Worksheet with version 3.0.3. This will affect the creation of Device Link profiles as well. The original 3.0 version of ColorThink Pro works fine for this - it will produce a clean ColorCast or Device Link profile with no tint. I would recommend using the 3.0 version for this procedure as a work around until we can get that bug fixed in the next version. You can download the Mac version with this link:
www2.chromix.com/colorthink/down … nkPro3.dmg

Choosing a smaller grid resolution than 33 x 33 (the largest) does not result in degraded image quality. It might result in color transformations being slightly less accurate, but in most cases you’d have to go pretty small to get a noticeable effect. In fact, a smaller grid size may result in smoother transitions between colors as the transition points will be interpolated mathematically rather than locked into a grid. 17 x 17 or 25 x 25 should work fine.

Thank you, Pat. This makes sense. I apologize if my questions are rudimentary. ColorThink is new to us and I am exploring it to understand as much about it as possible. So, I appreciate your patience.

I didn’t know that ColorCast profiles were intended to replace a RIP. But, that too makes sense. I was glad to see that the colour looked close to the expected result when the proof was printed through PhotoShop. I am even happier to hear that the overall background tint is a bug because I was not able to envision what I may have done wrong this time.

When I printed the proof through the RIP, I am quite sure that no other management was involved. I did not use Simulation mode (in fact we never have, except for tests you have suggested), RGB was not involved, the image file had no profile tagged to it and ColorBurst was configured to ignore embedded profiles anyway. But it’s input profile area was set to GRACol. So, I am very curious as to why it altered the colour so much and tripped over (failed to print) with the CC profile to begin with.

Thank you for the link to version 3.0. We will run the test through it as you suggest.

Regarding the smaller grid resolution, it was the color transformations being slightly less accurate that I was concerned about. I mentioned image resolution only to illustrate what I meant. I understand and am glad to know that the difference between 33x33 and 25x25 should not be noticeable. I also appreciate that fewer points results in smoother curves and transitions yet less accuracy is the resulting consequence of lower grid resolution.

Thanks again for your help with this. ColorThink and ColorCast are excellent tools.

Paul