topic Re: Color Print Dilemma in AutoCAD Forum

Color Print Dilemma

omorah — Thu, 08 Feb 2024 23:13:35 GMT

Hello folks,

I really need some help in trouble shooting where my issue would be from.

I cannot print a specified color to our printer to come out at least, very close to the chosen color from the computer.

Please see attached AutoCAD 2024 file to see if your printed result (paper copy) would look close enough. With my printer, none of the colors come close. The Canon technician took the Word file and their printer also did not print out correctly. Maybe it's in the way I assign the colors.

Also, I have a post in the TenForums on the same issue.

https://www.tenforums.com/drivers-hardware/211031-printed-color-dilemma.html#post2606946

Cheers

Re: Color Print Dilemma

Valentin_CAD — Fri, 09 Feb 2024 09:30:57 GMT

@omorah ,

Every plotter / printer will have some variation on the output.

You need to have a technician calibrate the colors.

Adjusting the Color

Output color does not match color in drawing

Re: Color Print Dilemma

Cadologist — Fri, 09 Feb 2024 13:40:30 GMT

In addition to Emilio's reply (100% agree) - I went back/forth with HP in the past regarding a similar issue. Prior employment experience, the client's logo had a specific color, to which, plotted out purple vs. blue. Because it was the logo, it was obviously important to get the color to match. After countless adjustments, etc. the output just wouldn't match perfectly. IIRC we ended up printing to a different printer, and even then there were still slight variations.

@omorah have you tried using a True Color (adjust HSL/RGB and Luminance) vs. an Index Color?

Re: Color Print Dilemma

omorah — Fri, 09 Feb 2024 21:25:57 GMT

The AutoCAD file "04 AutoCAD 2024.dwg", has two True Color samples in there, "0,0,255" & "16,25,214".

Re: Color Print Dilemma

omorah — Fri, 09 Feb 2024 21:31:10 GMT

Yes, I understand that what I see on the screen is NOT what I will get on paper.
The printed copies are, in my opinion, just too way off.
The Canon technician came to do some adjustment, still not what I am expecting.
I'll keep trouble shooting.
Thanks.

Re: Color Print Dilemma

leeminardi — Fri, 09 Feb 2024 23:20:39 GMT

Computer screens use the three additive primary colors of red, green, and blue whereas the subtractve primary colors mageta, yellow, and cyan are used to print on paper.

The conversion factors beween the two systems in not linear and very complex. The difficulty of the coversion from screen to printed paper is made even more complex due to the lack of color calibration of most computer screens and the need to use dithering (the digital equivalent of halftone) to adjust the intensity of primary colors used in printing.

I've changed the background color to black in your file to decrease the perception differences due to having a black vs. white backgrund. The screen colors are on the left and the printed pape colors are on the right.

Using a color picker the values for red, green, and blue for the two sets of index colors were recorded. The Excel image below shows the results.

Column C show the result of using the color picker in the AutoCAD drawing file. The RGB values are what they should be. Column D shows the result of the changes made in the process you used to captures the screen colors and save as a jpg file. Jpg's include some compresssion so the color is not uniform throughout the rectangular area. The varitation is more of an issue in column E that is the result of scanning a paper print and then savig as a jpg. The changes could be due to color deviations in your monitor or other factors. Column G is the difference between the ideal color (column C) and the scanned jpg file color. As can be seen the variation is all over the place due to the conversion from RGB to CYM (cyan, yellow, and magenta) and back.

High quality color printers are capable of matching screen colors to paper prints. Photographic techniques that work directly from a screen image provide good results too. If you do not seek to create photorealistic prints but just want a line drawing with colors closer to what you see on the screen I suggest making a test file of different combinations of red, green, and blue and see how they print. From those results you can swap the colors you use in your active file to get better results. For example, since the AutoCAD red appears to print more with an orange tinge, I would replace red with a color with some blue to counter the excessive yellow used in printing.