Removing minor colour casts in prints

[Rusty Pixels]

I'm using a Canon GP 4000 40" printer at a business centre and the prints have a slight tobacco tint to them. Its not major but I'm trying to get as close to neutral as possible. How do I create a test strip type of print that can help recognise what the tint is and how to correct for it? It would be great if there was a colour wheel with minor colour changes through say blue and cyan combos that you could print to see which colour combo would eliminate the tint or cast in the print, rather than having to drive back each day with another random test.

[davescm]

Colour management is designed to overcome such isdues. The correct way is to print using the colour profile for the printer, ink and paper combination. That could either be a profile created for that individual printer or, next best, a profile downloaded for the printer and paper. This automatically corrects colour.

If you are directly connected to the printer, install the profile, choose Photoshop manages colour, and select the profile in the print dialogue. If you are sending the image file to a 3rd party to print, ask what profile they want you file to have embedded. If they cannot tell you - move on and find another printer.

Dave

[Rusty Pixels]

Thanks Dave - that works for pro labs but this is a small town with a large format printer that is not managed by professionals. I can't find an ICC for the printer itself and I'll try to find out what paper they use, but even so, there must be a Ps technique somewhere for manual hue correction . I can't recall the name but we did a technique at photo college on silver bromide printing in the pre-electronic days.

[NB, colourmanagement net · Accepted solution]

@Rusty Pixels colour correction of this type isn't simple.

You could get someone to make an ICC profile and then all the users of this public machine could stop wasting paper on 'tobacco tinted' prints.

If you'd like to try manually colour-correcting pre printing again - here's an idea.

It might be a struggle because the colour shift may not be global. 

The [possible] solution to the colour cast is that you'll need to take the onscreen image in the opposite direction to what was printed, then make a new print

- if the print was dark you'd lighten an image before sending to print. It's quite a bit harder with off-colours though.

SO, this might make it easier - 

Take a test image (a composite image is best =

like this one - please go here and download the Adobe RGB testimage: https://www.colourmanagement.net/index.php/downloads_listing/

Now print it with printer and Photoshop settings you can remember for next time 

Take the resulting tobacco-tinted print to your computer. View it in good daylight.

(I am hoping your screen is calibrated and profiled so we can trust it?)

Use Photoshop's adjustment layer/s to match the screen appearance to the print. (i.e. add the tobacco tint)

You might manage it with just a Hue/Saturation adjustment layer*. Make any "tobacco" adjustment layers into a layer set.

*It's important to do this with layers, so you can disable them later. 

Now make a new set of adjustment layer/s to remove the tobacco cast you added - i.e. get the image back to normal.

Switch off the 'tobacco cast' set of adjustment layers or layer you used, leave the second set of layer/s checked on, so now your image is probably looking a bit blue/green [the opposite of tobacco], that’s what this printer needs it seems.

Duplicate the image with all its layers saving the original with layers, so you can go back and adjust again if needed

On the copy - Delete the "tobacco layer/s"

flatten

print. 

you're unlikely to hit it dead on first time but it a should be solid start

I hope this helps
neil barstow, colourmanagement net - adobe forum volunteer - co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management
Help others by clicking "Correct Answer" if the question is answered.
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[Rusty Pixels]

Thanks Neil - that's an excellent idea of reverse engineering and means I'm not messing around randomly. I recently purchased and Eizo monitor and Eizo screen calibrator so that side is taken care of. I'll have a look at your site that looks like a good reasource.

[NB, colourmanagement net]

@Rusty Pixels thanks I hope the procedure I described helps. Please let me know

I hope this helps neil barstow, colourmanagement net - adobe forum volunteer - co-author: 'getting colour right' google me "neil barstow colourmanagement" for lots of free articles on colour management Help others by clicking "Correct Answer" if the question is answered. Found the answer elsewhere? Share it here. "Upvote" is for useful posts.

[Rusty Pixels]

I just got the test print back using the technique you suggested and its very close to neutral. I won't go overboard as its not a supported printer, but I got the density right and the tobacco hue is gone. Now for some actual prints!

[NB, colourmanagement net]

@Rusty Pixels wow, well done, you hit it first time!

It's great I could help with my off-the-wall adjustment idea!

I hope this helps neil barstow, colourmanagement net - adobe forum volunteer - co-author: 'getting colour right' google me "neil barstow colourmanagement" for lots of free articles on colour management Help others by clicking "Correct Answer" if the question is answered. Found the answer elsewhere? Share it here. "Upvote" is for useful posts.