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Anonymous

Answered

Why do some printers print RGB and some CMYK if all printers are CMYK..?

Forum|Forum|6 years ago
March 15, 2019
6 replies
44273 views

Hi!

I'm currently extremely frustrated with printing services online that convert files to CMYK for their prints.
Such as banners, business cards and special prints such as Holographic prints.

If I understand it correctly, all printers print in CMYK. But how come my Canon Pro-300 prints my RGB files perfectly to where they look identical to what I see on screen, vibrant, saturated, glowing.. where as 3rd party printing services generally come out looking as if I changed my RGB file to CMYK in photoshop. Flat, desaturated, washed out and generally trash.

If ALL printers print in CMYK, how can I adjust my images at home so that what I get from 3rd party printers is as good as my home prints?

The CMYK colorspace is horribly limited and no amount of adjustment layers will make it look as vibrant as the RGB file yet my printer can print the RGB file perfectly.

Please bestow your wisdom upon this confused noob.

Thank you for your time.

This topic has been closed for replies.

Correct answer Dov Isaacs

To answer your original question and reconcile that with the other good responses on this thread:

In fact, there are no RGB printers. You either have a printer with CMYK (cyan, magenta, yellow, and black) inks or a printer, typically higher end inkjet devices, that has additional colorants (often either orange and green or light cyan, light magenta, and gray) to allow gamut expansion when converting from RGB colors.

On your home computer, whether MacOS or Windows, unless your printer is either a PostScript or a direct PDF printing device, the print drivers use an RGB printing model. This has some interesting ramifications.

If you print from Adobe Acrobat or Reader to a PostScript printer, you will get colormetrically-correct RGB to CMYK conversions that often seem “dull” compared to the colors you see on-screen which are quite frankly, out of gamut for a CMYK printer.

If you have a typical low-end home color printer, whether toner or inkjet based, there still are only CMYK (cyan, magenta, yellow, and black) inks. Depending upon the print driver's settings, many print drivers will not do a simply ICC profile-based RGB to CMYK conversion, but rather, use “secret sauce techniques” to try to punch up the colors, especially what one may describe as “office colors” such as the bright colors that you may typically see in a PowerPoint presentation or Excel spreadsheet. What is printed is not colormetrically correct, but rather, “pleasing” and not the “dull” colors you would get from a colormetrically-correct ICC profile-driven RGB to CMYK conversion.

If your home color printer is a “photo printer” with additional colorants, your printer driver is likely taking advantage of those additional colorants when converting from RGB to CMYK + the additional colorants to expand the gamut and give you colors that really “pop.”

In terms of what you do when you go for commercial printing, there are a few issues:

(1) If you provide the commercial printer with a CMYK-only PDF file, you are getting exactly what you should expect even if the commercial printer has a device with additional colorants. You have already eliminated the possibility of expanded gamut by the conversions to CMYK.

(2) If you provide the commercial printer with a PDF/X-4 file, for example, in which the RGB colorants (such as for images or RGB-based vector items) are maintained in RGB with their ICC profiles and the printer has devices with more than CMYK colorants (quite often the case for wide-format banners, signs, and specialty items), then you should not be seeing this problem assuming that the commercial printer knows that you need this expanded gamut.

(3) For business cards, for example, most printers will use a CMYK device. If you have special needs, you need to advise your printer of such needs and expect to pay higher prices for printing on devices that have extra colorants to expand gamut!

Remember that you can preview what your PDF file will look like in Acrobat with the Output Preview feature as well as the Overprint Preview option (under Display Preferences).

- Dov

C

Crazy26005515r1b9

Participant

Maybe because they don't give a shite about your files. They hire students who just hit the 'PRINT' button.

I went shopping for a compact-camera and this camerashop also did printing.

Ipicked up a few examples of prints laying around in that shop. Terrible washed colors. I could not believe anyone hands their digital stills in like that.

T

Test Screen Name

Legend

A few years ago Pantone's Hexachrome technology was the way forward. Six ink printing, with Pantone software to convert RGB to the six channels needed to print. Nice results. I wonder what happened to it.

Dov Isaacs

Legend

Pantone's business model has changed dramatically since the early 2000's when Hexachrome was actively marketed by Pantone. Pantone no longer sells inks, but rather the formulations and definitions. Hexachrome was Pantone's process for expanded gamut printing using special orange and green inks to expand the gamut beyond the colors supported by process CMYK. In order to use it, you needed to do special file preparation with Pantone software to yield additional explicit O and G channels. Typically this Hexachrome preparation was done in Photoshop with a Pantone plug-in. I believe that Pantone dropped the Hexachrome system as ICC color management became more mainstream and most major printer vendors were providing means of extending gamut with use of extra inks in conjunction with ICC color management being employed to convert wide gamut RGB colors at RIP time.

- Dov

- Dov Isaacs, former Adobe Principal Scientist (April 30, 1990 - May 30, 2021)

S

Shelleysellseashells

Participant

Wowww. This is some invaluable info for a newbie like me! I've been doing this on and off for 7 years and I still never fully understood what the deal was with the RGB to CMYK colour conversion even though we were taught this breifly in university.

Do you have any thoughts on which RGB colour setting to select on output for PDF/X? I've always just gone with the default sRGB IEC 2.1 because I simply have no idea how it will affect the printing process on a CMYK printer.

I'm currently trying to print a neon glow effect typeface as a test for customers who will either print domestically or take to local commercial printers. I want to give them the best advice on how to print at home and/or how to communicate what is needed to their commercial printers which is how I ended up here.

A

Anonymous

Thank you! This explained everything!

J

johnnyvn

Participant

Haha, I have the exact same frustration.

Is there any way that professional print companies print colors (using any method) that are as vibrant as the RGB colors I see on my MacBook Pro screen?

I, too, designed a business card with vivid colors, only to run into this limitation. Can't believe the entire world putting up with this, given the advanced technologies everywhere in our world...

Haha, I'm obviously a newbie to this!

Dov Isaacs

Legend

to add to this: designers work around this by using specific Pantone colours.

Until now, I haven’t seen a professional printer using more than CMYK + Pantone for volume work.

Specialized service provider are offering print sevices mainly for photographers, but that are as said, expensive services and they do not do volume work.

Abambo wrote

to add to this: designers work around this by using specific Pantone colours.

Until now, I haven’t seen a professional printer using more than CMYK + Pantone for volume work.

Specialized service provider are offering print sevices mainly for photographers, but that are as said, expensive services and they do not do volume work.

Au contraire, mon ami …

Quite a bit of commercial printing, not just photographic printing, is done with process CMYK + one, two, or even three spot colors, especially when dealing with packaging and much printing associated with corporate branding (think Coca Cola red, Pepsi Cola blue, Kodak yellow, etc.) Of course this is “volume work.”

With regards to use of “specific Pantone colours,” one must distinguish between Pantone spot colors and Pantone “spot colors” such as those provided in Adobe applications as PANTONE+ Pastels & Neons, PANTONE+ Metalllics, PANTONE+ Premium Metallics, and PANTONE+ Solid (coated and uncoated versions) versus PANTONE+ CMYK and PANTONE+ Color Bridge swatch collections.

The former group are spot colors designed to be printed with inks exactly matching the specified colors. These colors are specified as spot colors with Lab, device independent alternate color definitions. A large percentage of these colors (but not all of them) are way “out of gamut” for process CMYK printing – be exceptionally careful in choosing any of these colors if you plan to use only process CMYK printing. It is not the responsibility of your print service provider to do this for you. If you do use these colors for artwork printed with process CMYK printing, be sure to set options when exporting PDF via the Ink Manager to treat these as non-spot colors in which case the Lab alternates will be used in the PDF file. (This is critically important if transparency is involved!)

The latter group of Pantone swatches are designed for selecting colors to be printed using only process CMYK. You obviously won't find those wild, out-of-gamut colors in these swatches, but they are generally safe for use with process CMYK printing. What you do need to be careful of is that the CMYK values of these swatches are DeviceCMYK, are not color managed (no designation as to which CMYK color space the colors were designed for, and can differ in final appearance depending upon the CMYK characterization of the print process used.

- Dov

- Dov Isaacs, former Adobe Principal Scientist (April 30, 1990 - May 30, 2021)

Dov IsaacsCorrect answer