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Author Topic: "Start in CYMK" ??  (Read 8444 times)

MBehrens

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"Start in CYMK" ??
« on: May 20, 2016, 08:09:46 pm »

http://petapixel.com/2016/05/20/difference-rgb-cmyk/

This video at 1:40 states that you "should start in CYMK and not convert later. "

Not sure what this means. I use Lightroom CC and so I am working in ProPhoto RGB. I don't have the option to work in any other color space. And if I could work in CYMK, wouldn't I need to convert to RGB on the fly? I need to be converting from RGB to CYMK somewhere along the pipeline, seems on the way to the printer would be a good place.
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digitaldog

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Re: "Start in CYMK" ??
« Reply #1 on: May 20, 2016, 08:17:31 pm »

http://petapixel.com/2016/05/20/difference-rgb-cmyk/

This video at 1:40 states that you "should start in CYMK and not convert later. "

Not sure what this means. I use Lightroom CC and so I am working in ProPhoto RGB. I don't have the option to work in any other color space. And if I could work in CYMK, wouldn't I need to convert to RGB on the fly? I need to be converting from RGB to CYMK somewhere along the pipeline, seems on the way to the printer would be a good place.
Well, after that 1:40 timeframe, just ignore the rest of the video!
There is no such thing as a CMYK capture device (scanner or camera) so, you've got to produce CMYK at some point in the workflow FROM RGB. The video doesn't tell you that.
Convert to CMYK towards the very end of the workflow; when you are targeting for a specific output device and you have an ICC profile for that conversion.


http://digitaldog.net/files/CMYKPart1.pdf
http://digitaldog.net/files/CMYKPart2.pdf
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Tony Jay

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Re: "Start in CYMK" ??
« Reply #2 on: May 20, 2016, 08:20:56 pm »

Frankly I would not let this confuse you.

Do yourself a favour and get the "Camera to Print and Screen" video tutorial series available on this website.
Everything will be put in perspective for you.
Apart from anything else you will get to experience the peerless and irrepressible Michael Reichmann interacting with his great friend Jeff Schewe.
That interaction alone is worth any price of admission and the learning experience with respect to the workflow right the way from camera settings all the way to matting and framing is unmatched.
I would regard this series as obligatory viewing.

Tony Jay
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Mark D Segal

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Re: "Start in CYMK" ??
« Reply #3 on: May 20, 2016, 08:29:39 pm »

I should add to Tony's comment that if you have bought your 12 dollar membership to the site, the tutorials are all accessible for no further charge - there isn't a better value on earth.

The OP does not provide any context of what he/she is working with and toward. If this is a case of producing a standard inkjet print from a standard inkjet printer (Epson, Canon, HP) the printers EXPECT RGB data so you work the files in an RGB color space and send them to print that way. Any necessary conversions to the colours the printer uses to produce the correct recipe for your photo is handled between your computer operating system's colour management module and the printer driver. You need not concern yourself about anything CMYK. Forget that it exists. If on the other hand you are aiming the files at some other device, such as an offset press, get specific instructions from the printing house about how they want the files prepared.
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Doug Gray

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Re: "Start in CYMK" ??
« Reply #4 on: May 20, 2016, 08:44:32 pm »

I should add to Tony's comment that if you have bought your 12 dollar membership to the site, the tutorials are all accessible for no further charge - there isn't a better value on earth.

I paid the $12. Definitely worth it - by a large factor.
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AlterEgo

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Re: "Start in CYMK" ??
« Reply #5 on: May 20, 2016, 08:57:46 pm »

There is no such thing as a CMYK capture device (scanner or camera)
but there were CMYG CFA sensors in some cameras... not K of course, but close  ;D
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digitaldog

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Re: "Start in CYMK" ??
« Reply #6 on: May 20, 2016, 09:24:33 pm »

but there were CMYG CFA sensors in some cameras... not K of course, but close  ;D
What's the old saying about close and horseshoes and atom bomb?
There is no such thing as a CMYK capture device (scanner or camera).
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Schewe

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Re: "Start in CYMK" ??
« Reply #7 on: May 21, 2016, 01:32:34 am »

This video at 1:40 states that you "should start in CYMK and not convert later. "

I think this may be out of context...I think this video is for designers not photographers...there's  big difference. Illustrator and InDesign really want to be driven as CMYK. Digital capture on the other hand are by nature RGB devices and so are the printers used for printing photos on Epson or Canon printers. The printer prefer getting RGB images and does their own special separations.

That's the ting about the Internet...ya gotta be really careful who you listen to.
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Ernst Dinkla

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Re: "Start in CYMK" ??
« Reply #8 on: May 21, 2016, 04:01:28 am »

I think this may be out of context...I think this video is for designers not photographers...there's  big difference. Illustrator and InDesign really want to be driven as CMYK. Digital capture on the other hand are by nature RGB devices and so are the printers used for printing photos on Epson or Canon printers. The printer prefer getting RGB images and does their own special separations.

That's the ting about the Internet...ya gotta be really careful who you listen to.

With many designer shops advertising their versatility in multimedia designs I doubt CMYK to start from is a good workflow for them these days. Setting RGB color description in designer software is not that difficult. To add to Andrew's comment, "There is no such thing as a CMYK capture device"; There's no CMYK display in the studio either. And in theory and practice any conversion from RGB to CMYK is more reliable than the other way around.

Next Drupa will show even more inkjet based web printing system, in particular for the packaging industry, the only branch that grows. Basically not different from the printers we have. Most RIPs cover both RGB and CMYK color management, that is not the bottleneck. It is the graphic industry that is conservative in its traditional CMYK workflow.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2016 update, 700+ inkjet media white spectral plots

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Bart_van_der_Wolf

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Re: "Start in CYMK" ??
« Reply #9 on: May 21, 2016, 06:04:50 am »

I think this may be out of context...I think this video is for designers not photographers...there's  big difference. Illustrator and InDesign really want to be driven as CMYK.

I think Jeff is correct, because the sentence goes: "When designing for print ...".
Context matters as usual, so when designing in CMYK, it is not a good idea to convert to RGB and later back to CMYK again. Each conversion is prone to add losses, because the color spaces do not fully match. Also, in CMYK colors to be printed can be created in different ways, depending on the settings for the printing press (e.g. dot-gain and UCR settings and ink types and substrate color used).

Quote
Digital capture on the other hand are by nature RGB devices and so are the printers used for printing photos on Epson or Canon printers. The printer prefer getting RGB images and does their own special separations.

Yes, and it's a single conversion, from RGB to (usually) many more ink-colors than only CMYK, instead of a round-trip. A conversion from RGB to CMYK to printer ink-colors, is also 2 conversions, and the CMYK step is superfluous and damaging to the final image quality.

So when the image originates from the computer and is designed for a printing press, by all means do start and stay in CMYK (with the correct settings for the output modality). But when an image originates in RGB, like from a digital camera, limiting to one final output profile conversion (either a CMYK separation or a many ink color inkjet output, or an RGB C-print modality) is best.

Cheers,
Bart
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Czornyj

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Re: "Start in CYMK" ??
« Reply #10 on: May 21, 2016, 07:32:09 am »

So when the image originates from the computer and is designed for a printing press, by all means do start and stay in CMYK (with the correct settings for the output modality).

As a graphic designer I never start in CMYK, and think that at the end of the day it's always a bad idea. First of all, when you're making a design in CMYK it's always limited and optimised for specific CMYK, usually the CMYK of a standard sheetfed offset print on class 1/2 papers, which is limiting factor for designs that are printed with various printing devices, published electronically etc. Furthermore - each CMYK profile is LUT type, so any editing is much more destructive than in case of any matrix type profile of a RGB synthetic editing color space, not to mention that editing PS tools that work in CMYK mode are much more limited. I much prefer working in RGB with enabled softproofing of CMYK device I predict to use -  in my case it's more much more flexible and convenient approach.
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Mark D Segal

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Re: "Start in CYMK" ??
« Reply #11 on: May 21, 2016, 07:47:30 am »

As a graphic designer I never start in CMYK, and think that at the end of the day it's always a bad idea. First of all, when you're making a design in CMYK it's always limited and optimised for specific CMYK, usually the CMYK of a standard sheetfed offset print on class 1/2 papers, which is limiting factor for designs that are printed with various printing devices, published electronically etc. Furthermore - each CMYK profile is LUT type, so any editing is much more destructive than in case of any matrix type profile of a RGB synthetic editing color space, not to mention that editing PS tools that work in CMYK mode are much more limited. I much prefer working in RGB with enabled softproofing of CMYK device I predict to use -  in my case it's more much more flexible and convenient approach.

I agree with Marcin about this, and in fact Michael had described a similar procedure years ago on this website for the production of one of his print books. The problem with this thread, as I mentioned earlier on, is that OP has not said anything about the context of his work - where he's starting from and where he wants to end up. It's always a good idea for an O/P to provide enough information allowing the participants to provide more directly useful answers.
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Mark D Segal (formerly MarkDS)
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Czornyj

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Re: "Start in CYMK" ??
« Reply #12 on: May 21, 2016, 08:29:27 am »

I agree with Marcin about this, and in fact Michael had described a similar procedure years ago on this website for the production of one of his print books.

Speaking of Photobooks - digital presses used for photobook printing (toner and electroink based) usually have wider gamut than conventional sheetfed offset, so preconversion to a standard CMYK profile limits the potential of these devices. Here's a simulation of a CMYK preconverted image and an ECI RGB image directly converted to my private's Xerox DC252 profile:
« Last Edit: May 21, 2016, 08:32:34 am by Czornyj »
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Mark D Segal

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Re: "Start in CYMK" ??
« Reply #13 on: May 21, 2016, 09:54:41 am »

Yes, very good comparison Marcin - the differences are subtle but nonetheless present - especially in the bright green/yellowish green and magenta/red parts of the colour spectrum.
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Mark D Segal (formerly MarkDS)
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digitaldog

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Re: "Start in CYMK" ??
« Reply #14 on: May 21, 2016, 11:56:15 am »

Yes, very good comparison Marcin - the differences are subtle but nonetheless present - especially in the bright green/yellowish green and magenta/red parts of the colour spectrum.
I suspect the differences would be far less subtle if you could view the actual printed output.
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Mark D Segal

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Re: "Start in CYMK" ??
« Reply #15 on: May 21, 2016, 12:00:52 pm »

I suspect the differences would be far less subtle if you could view the actual printed output.

Sure - good point.
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Mark D Segal (formerly MarkDS)
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Doug Gray

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Re: "Start in CYMK" ??
« Reply #16 on: May 21, 2016, 02:09:11 pm »

This is a very good technical paper regarding CYMK, and variants.

http://wiki.epfl.ch/edicpublic/documents/Candidacy%20exam/dcihchap5devchar.pdf

It goes through many of the issues involving profiling and mathematically characterizing the over determined CMYK space. When people start with a specific CYMK space conversion to another CYMK space will introduce more error than that which occurs going from an initial RGB space to a CYMK space. However, RGB spaces are very easy to introduce colors outside a CYMK gamut but as long as one is inside the gamut initially using RGB provides better results going to different CMYKs. And, as noted by commenters, images from scanners and cameras start in RGB.
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Czornyj

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Re: "Start in CYMK" ??
« Reply #17 on: May 21, 2016, 04:48:03 pm »

I suspect the differences would be far less subtle if you could view the actual printed output.
Exactly!
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MBehrens

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Re: "Start in CYMK" ??
« Reply #18 on: May 23, 2016, 10:30:59 am »

OP here. I'm not trying to do anything, as I stated the statement in the video piqued my curiosity. I'm a photographer and not a graphic designer so a CYMK workflow seemed very odd to me.
The conversation here really helped me to understand. As usual. Thanks!
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digitaldog

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Re: "Start in CYMK" ??
« Reply #19 on: May 23, 2016, 11:05:15 am »

I'm a photographer and not a graphic designer so a CYMK workflow seemed very odd to me.
IF you never have to deal with CMYK, consider yourself lucky! An old saying I recall that's kind of amusing: God (I prefer DOG) created RGB. Man created CMYK: what would you rather use?
CMYK aka the devils color space  ;D
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