Color adjusting tool for office printer

Question

Our office printer is not color calibrated and probably never will be.

The colors do no match the colors we get from professionally printed material based on the same file.

I want to use our office printer to get as close to our 6 corporate colors as possible. I.e. make two versions of the files: One for professionally printing and one for our office printer.

Is there a elegant way I can figure out which color values I should use in LibreOffice that will get me close to these 6 colors?

I am thinking some sort of document, where I give a single color and this will then generate colors that are close in value to this color with the RGB values for these generated colors. Then I can print that document, compare the squares to the target colors based on professionally printed material, select the closest RGB value, and try again until I find no closer color.

Answer 1

The problem with your approach is that as soon as you get a new printer, you need to recreate every asset. So you want a printer that is a slave to your process, not the other way around.

You will never get exact color, but the best way to handle this is to calibrate your monitor (rent a monitor calibration device from a photography shop) and ensure that what you see on the monitor is as close as it can be to what you see on the printed products from your print provider.

The next step is to look carefully at the programs you are using. Not all of them will handle color well. Some will work well if you first export to PDF and then use PDF software with good color management. This way you can get a reasonable "soft proof" on your screen using trustworthy software, and then the prints will be easier to create.

The next step is to not use ICC profiles on your printer, but rather set up the printer's drivers to never auto-adjust color: no "vivid" no "photo enhance mode"--no nothing. Set it up for complete manual, no auto-adjust no ICC. Many major printer drivers have all three choices.

Then you make minor manual saturation, contrast, and color adjustments in the printer driver setup to get your printouts inside the realm of realistic. If possible save that as a preset, if presets are not possible write them down (and be sure you write down the adjustments you made on your samples when working this out so you can make comparisons). Disable in-printer auto-color adjustment and us this preset every time you need to print.

If you focus on the process this way, you will be able to use the same files for both in-house and print provider without alteration.

Answer 2

Generally home/office printers can only print RGB image files. The artwork for professional printing is often made in CMYK. So that may be your problem. Make sure the images your are printing are not in CMYK. If necessary ask your designer to provide RGB versions of the files.

Answer 3

To print "proper" CMYK on office printer you need: - printer jobfile that will translate your RGB to desired CMYK for that particular printer. - color profile for your program that will translate proper RGB from color used in the document to the exported file you will print.

To answer your question, there is no elegant way. Especially in program like Libre which is not designed in any way to handle colors properly.

What you want to do is to take spectrophotometer check printed colors and see how much they are off from target one, then fix the color in Libre with "around" amount.

The main problem you face is that Libre don't specify what profile they use to handle color. So you may have on your screen 45% Black. Which Libre send to machine as 145,152,153. And then printer can translate it to C15,M15,Y15,K35.

At some point you would need at least semi-professional program that would give you some control over toner/paint amount.

Answer 4

I ended up with this:

Using this Python program I generated an html-file that had cells with values around the RGB values.

#!/usr/bin/python

import sys

col=int(sys.argv[1],16); # 3d7d7c
step=int(sys.argv[2]); # 3;
size=8;
acol=[[[0 for x in range(size)] for y in range(size)] for z in range(size)]

for r in xrange(size):
  for g in xrange(size):
    for b in xrange(size):
      acol[r][g][b]=col + step*(r-size/2)*0x10000 + step*(g-size/2)*0x100 + step*(b-size/2)*0x1;

for r in xrange(size):
  print "<table>";
  for g in xrange(size):
    print "<tr>"
    for b in xrange(size):
      print("<td bgcolor='#%0x'>#%0x<br/></td>" % (acol[r][g][b],acol[r][g][b]));
    print "</tr>\n"
  print "</table>";

I then opened this in LibreOffice and printed it.

Then I compared the printed output with the professionally printed colors. Both visually and by using a scanner and select-by-color in Gimp (scanning both the professionally printed and locally printed in a single image).

Then I selected the best matching values.