Recent

Author Topic: how converting RGB to CMYK with text as 100% Black  (Read 3150 times)

0 Members and 1 Guest are viewing this topic.

Offline hassan_65

  • New Member
  • *
  • Posts: 1
how converting RGB to CMYK with text as 100% Black
« on: November 30, 2014, 04:17:38 PM »
Hi guys
I have a question that  how converting RGB to CMYK with text as 100% Black?
I think if I can make a script in Photoshop or something like that I will do it
But I dont know anything to make a script
for example a script
if  R= 255  G=255  B=255
convert it to 100% black
what do you think ? it will work ?

Offline Made in Taiwan

  • Full Member
  • ***
  • Posts: 220
Re: how converting RGB to CMYK with text as 100% Black
« Reply #1 on: December 01, 2014, 07:40:03 AM »
Do you only have a pixel-based file like JPG or TIF? That's gonna be tough but you can try it. It would be easier if you had a PDF (I mean one with embedded fonts or at least outlined fontshad, not one created from the pixel file), because in that case you could use the built-in Acrobat change color tool or Pitstop if available.
Working in Prepress is very difficult. God chose only the best to do this job.

Offline Tracy

  • Ninja Master
  • **
  • Posts: 8411
  • Gender: Female
Re: how converting RGB to CMYK with text as 100% Black
« Reply #2 on: December 01, 2014, 01:27:21 PM »
If it's not actual text, I don't think there is anyway of making it 100K
I'm not that smart tho :laugh:

Offline Joe

  • Master of Nothing
  • Administrator
  • Ninja Warlord
  • *****
  • Posts: 38775
  • Gender: Male
    • B4Print.com
  • Gender: male
Re: how converting RGB to CMYK with text as 100% Black
« Reply #3 on: December 01, 2014, 01:30:12 PM »
The only way I can see even getting close is to make a CMYK profile with the black generation set at maximum black but that would be dangerous to apply blindly to all images.
Mac OS 11.5.2 Big Sur | Prinergy 9.0.1.125 | Adobe Creative Cloud 2021 | TWO Fuji CTP Units

I'm Sorry I Hurt Your Feelings When I Said You Were Stupid. I Honestly Thought You Already Knew

Offline cpking

  • New Member
  • *
  • Posts: 7
Re: how converting RGB to CMYK with text as 100% Black
« Reply #4 on: January 26, 2016, 02:27:25 AM »
For text it can be converted in fully 100% black without that it should not possible i think.

Offline mattbeals

  • Just a dude
  • Hero Member
  • *****
  • Posts: 885
  • Gender: Male
    • Matt Beals
Re: how converting RGB to CMYK with text as 100% Black
« Reply #5 on: January 26, 2016, 02:33:18 PM »
Convert with perceptual rendering intent, that will get the closest if not exactly what you want. Otherwise you need an device link  profile with GCR, or a device link that is smart enough to capture RGB/CMY blacks and keep them black. Generally though, perceptual will do what you want.
Matt Beals

Everything I say is my own personal opinion and has nothing to do with my employer or their views.

Offline swampymarsh

  • Full Member
  • ***
  • Posts: 165
Re: how converting RGB to CMYK with text as 100% Black
« Reply #6 on: January 27, 2016, 07:29:03 AM »
Presuming an RGB image with a separate RGB black text layer, convert to CMYK without flattening then change the text to K only.

If you only have rasterised text in a separate layer, add a channel mixer adjustment layer to the file above the text layer, using a clipping mask group so that only the text is affected by the channel mixer adjustment layer. Then set the channel mixer to monochrome and mix the channels until you have 0c0m0y100k.

If you only have rasterised text in a flattened image, you would need a mask of the text to limit the monotone channel mixer effect to only the text.

Keep in mind that one may need a 1 or 2 pixel trap between the K only text and the CMY plates, unless there is a good amount of GCR in the conversion and K tones meet the solid K.
« Last Edit: January 30, 2016, 01:46:30 AM by swampymarsh »

Offline Tracy

  • Ninja Master
  • **
  • Posts: 8411
  • Gender: Female
Re: how converting RGB to CMYK with text as 100% Black
« Reply #7 on: January 27, 2016, 01:38:21 PM »
Interesting, where is the channel mixer?
Photoshop is mysterious to me :laugh:

Offline Joe

  • Master of Nothing
  • Administrator
  • Ninja Warlord
  • *****
  • Posts: 38775
  • Gender: Male
    • B4Print.com
  • Gender: male
Re: how converting RGB to CMYK with text as 100% Black
« Reply #8 on: January 27, 2016, 01:45:14 PM »
PShop menu===>Image===>Adjustments===>Channel Mixer.
Mac OS 11.5.2 Big Sur | Prinergy 9.0.1.125 | Adobe Creative Cloud 2021 | TWO Fuji CTP Units

I'm Sorry I Hurt Your Feelings When I Said You Were Stupid. I Honestly Thought You Already Knew

Offline Tracy

  • Ninja Master
  • **
  • Posts: 8411
  • Gender: Female
Re: how converting RGB to CMYK with text as 100% Black
« Reply #9 on: January 27, 2016, 03:44:51 PM »
Thanks Joe, I also found Rt clicking on adjustment layer shows it too!
I'm a photoshop guru now :laugh:

Offline Joe

  • Master of Nothing
  • Administrator
  • Ninja Warlord
  • *****
  • Posts: 38775
  • Gender: Male
    • B4Print.com
  • Gender: male
Re: how converting RGB to CMYK with text as 100% Black
« Reply #10 on: January 27, 2016, 03:51:42 PM »
You go girl! :)
Mac OS 11.5.2 Big Sur | Prinergy 9.0.1.125 | Adobe Creative Cloud 2021 | TWO Fuji CTP Units

I'm Sorry I Hurt Your Feelings When I Said You Were Stupid. I Honestly Thought You Already Knew

Offline Ear

  • Fiya wata
  • Supreme Ninja
  • ***
  • Posts: 16314
  • Gender: Male
  • Nice Marmot, Man
Re: how converting RGB to CMYK with text as 100% Black
« Reply #11 on: January 27, 2016, 05:10:48 PM »
I see the forecast for today is cloudy with a chance of mattbeals. :hello:
"... profile says he's a seven-foot tall ex-basketball pro, Hindu guru drag queen alien." ~Jet Black