Blue onscreen purple on proof

Hi All

We are experiencing a problem with supplied CMYK scans from a customer. The scans are of paintings and we believe they have been converted to CMYK using a Euroscale V2 profile. A few of the scans contain a blue colour, for example as part of a dress. They look blue on a our calibrated monitors but they proof on our Dupont Largo as something more akin to purple. We have two standards on our Largo, EuroStandard and Gracol. These were only recalibrated last week and on an IT/8 target with 1617 swatches we are getting an average Delta E of about 1.1, so we know they are pretty accurate.

The colour break on the blue is in the range 100/90/30/40 <-> 100/85/36/21 which to me is somewhere in the middle between blue and purple., but it definitely appears blue on screen. The problem is the customer sees the blue and this is what they want. I'm finding it difficult to convince them that our proofing is accurate and that the problem is the way that this colour is being shown on their (and our monitors). We have re-calibrated our monitors and they reflect the purple better but we still cannot match it. I need have an understanding of why it isn't being represented properly and also what I can get the customer to do so it shows on his monitor better.



rich apollo

Well-known member
Re: Blue onscreen purple on proof


The numbers you cite are gonna' make purple. There's too much magenta.

Your post doesn't state it, but I gather that the scans are untagged. Are you in a position where you can contact the client and get the color space information?

Did the client send any hard proofs? If they've been relying on a proofing device you could have them print a profiling target in the same fashion - then you can read it, generate a profle, and use that as a source for the conversion into your preferred colorspace.

You could offer to profile their monitors, but there's no guarantee that they're working on monitors that are worth profiling.

Are you certain that the scans were done in RGB? Could they be scanning in CMYK? Geez that'd suck. That screws the pooch, badly.



Well-known member
Re: Blue onscreen purple on proof

Are the files tagged with a profile? What are your Color Management policies in Photoshop when opening a file? Do you preserve the embedded profile? If so, try assigning another CMYK profile (your usual CMYK working space) and see if that blue onscreen comes closer to what you are getting on proof. If so, you will need to open the image preserving supplied profile and do a CMYK to CMYK profile conversion to your usual working CMYK space.
Hope this helps.
Re: Blue onscreen purple on proof

As far as we know they were scanned RGB and converted to CMYK before the got to us using a Euroscale V2 profile.

I agree that these colour breaks are defintely heading towards purple but I can't explain why it looks so blue on screen. Not matter what Colour Settings we use in Photoshop we can't get the scan to appear purple on screen, it always remains blue (ish). It's not a calibration issue on the monitor as it's been calibrated/profiled with an Eye-one and Monaco, so it's just a preview issue but I'm a bit lost as to what to tell the customer.


Well-known member
Re: Blue onscreen purple on proof

The CMYK profile used is the problem. Why? The program that made it. ECI's ISO profiles (except the latest ISOcoatedv2 and ISOcoatedv2_300) have this problem.

Try getting the original RGB from customer (with profile embedded). Open, honoring/keeping RGB profile. Convert to official GRACoL2006_Coated1v2 or ISOcoatedv2 profile. The blue will be better (at least not turn purple), although not as good a blue as if GretagMacbeth made the profile (even from the same characterization data that was used to make the official profiles).


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