ColorSpaces in a DynaPDFMBS object

If I create a DynaPDFMBS document, and the images and colors were created in RGB
is there a way in code to

convert the whole document to CMYK colorspace

…in order to keep lazy printers happy without making me change/duplicate all my source code to use CMYK?

Short answer is no, as that isn’t the responsibility of DynaPDF.

If you have defined your colours using an RGB ICC colourspace and your images contain ICC profiles then the RIP attached to the target output device should do the conversion. This makes the PDF more generic than if you converted everything to CMYK up front (which requires you knowing the target device in advance).

If you did know the target output device you could attach its ICC profile to the PDF as an output intent. This would instruct PDF viewers to show colours as how they were printed.

Thanks for the reply Kevin.
I glazed over after ‘Short answer is no’ because I don’t understand profiles or what RIP means… (apart from ‘oh no, they died…’)


Thanks for confirming that my first response should remain ‘if they want CMYK, let the target device do it’

Be careful. If you don’t use ICC colourspaces then there is a good chance that the colours will be printed incorrectly.

Did I mention I don’t understand them. :slight_smile:

If you need the colours to be printed as accurately as possible then you will need to use ICC colour management. If you don’t care then just ignore it.

The basics are not hard to understand. If you Google ‘introduction to icc colour management’ you should find lots of sites with useful information.

The easiest way to think of color profiles is this: they are complex numeric systems that translate colors from one color space (say, RGB) into another (for example, CMYK) in a way that optimally represents the original color in the destination color space. The math of how color profiles work is far, far beyond my understanding so I won’t try to explain it here.

The reason they are necessary is that color spaces overlap, but not 100% - the RGB color space (perceived via light frequencies) is one of the largest and can represent almost any color, while CMYK (perceived as light reflecting off a surface printed using CMYK inks) is considerably smaller; there are colors that we can see in RGB that can’t be directly represented in CMYK due to the limitations of ink systems. Color profiles define what happens to these out-of-bounds colors through a variety of techniques.

They also “nudge” colors to ensure accurate reproduction - for example, if a CMYK device tends to create output that is slightly orange, the color profile will know this and adjust the colors appropriately to avoid an orange tint.

Ideally, all colors in a print stream are tagged with the color space that the color numbers represent. This often corresponds to the device that generated the color information: your cell phone’s camera has a particular color profile, as does your flatbed scanner. Output devices also have color profiles; your monitor, your printer, your cell phone’s screen, etc. The color engine takes all of this into account and is responsible for making the best effort at consistent color representation.

That’s why it’s important to use color profiles whenever possible. Color data that is not associated with a profile will get treated as generic data and may result in color shifts. They’re not likely to be extreme, but they can be enough to cause concern and color mismatches with other elements.

Support for color profiles is virtually ubiquitous at this point. Since the mid-90s, all the major image editing software supports color profiles; any digital camera you are likely to use is going to automatically embed a profile; even a screenshot taken on your Mac will have an embedded profile. All major operating systems process them.

The nice thing about color profiles and color management in general these days is that it happens silently, providing excellent results without any user intervention required. This quality of output used to be the sole domain of professionals with years of experience and it’s rather amazing how far we’ve come in the past 20-25 years in bringing this technology to the masses.

You could just continue to use RGB colors.
The printer would then use their standard RGB profile (probably SRGB) for converting colors to CMYK in the print process.

If you like to specify which RGB you like, you could add an output intent.
e.g. AddOutputIntent() and pass fokleritem for the ICC profile file.

Reading this info from MBS i think converting to a different color space should be possible. Though i have not tried it yet.

While leaving all in RGB is best way to achieve color accuracy, a lot of printers in germany, even the bigger ones, insist in sending PDF/X-1a files, which allows CMYK color space, only.

If this is the case then you need to request the required CMYK destination profile in order to produce the PDF/X-1a CMYK conversion.

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You can convert all colors to CMYK using our Optimize() function.

Or of course learn how to make an ICC colorspace using CreateICCBasedColorSpace.

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