CMYK viewing images

[Photog]

Hi all,

Apologies if this question has been asked before; I did a little search and couldn't get the answer I was looking for.

I'm currently going through the annoying process of converting 20 images to CMYK for printing, and when trying to correct the colour after conversion I've noticed that changes I make in PS are not reflected in the same way when viewing the image in Windows Photo Gallery. Images are more saturated in PS, and it seems like I need to make more extreme changes in colour/saturation in PS in order to get what I want when the image is saved and viewed in Windows Photo Gallery.

Which of these two is more accurate? And which will the prints come out as - the more saturated PS version or less saturated Windows Photo Gallery version?

Thanks in advance.

 

[dots]

Did you intendfor your post to include images? I don't see any.

 

[Photog]

Nope, when I asked which is more accurate, I meant viewing a CMYK image in Windows Photo Gallery or in Photoshop?

 

[MTVision]

"Be aware that it is possible to see colors in RGB that you can't make with CMYK.
They are said to be "out of the CMYK color gamut". What happens is that the RGB-to-CMYK translator just gets as close as possible to the appearance of the original and that's as good as it can be. It's something that everyone in the industry puts up with. So it's best to select any colors you use for fonts or other design elements in your layout using CMYK definitions instead of RGB. That way, you will have a better idea of how they will appear in your printed piece. Here's a common example: many programs translate the 100% Blue in RGB into a somewhat purple-looking color in CMYK. We recommend a CMYK value of 100-65-0-0 to get a nice clean blue. Working in the CMYK color space allows you to select the CMYK recipe, or "screen build", that gives you the results you want."


Is your photoshop in the cmyk colorspace? I don't know for sure if it matters.

 

[clanthar]

How are the photos being printed? Are you printing them yourself and if so on what kind of press hardware?

Joe

 

[clanthar]

Is your photoshop in the cmyk colorspace? I don't know for sure if it matters.

There's no such thing as a CMYK color space. Photoshop is capable of managing CMYK images, but that job must be output device specific. There's only CMYK that matches a specific press, plate type, ink and paper combination.

Joe

 

[KmH]

Color Management: Color Space Conversion

Color Management: Understanding Color Spaces

Both are part of : Tutorials on Color Management & Printing

Windows Photo Galley is not color managed as far as my understanding goes, while Photoshop is and you can choose the working color space in Photoshop.

 

[Garbz]

I'm currently going through the annoying process of converting 20 images to CMYK for printing,

And all my alarm bells went off.

What's your process that requires you to convert images for printing? The printing process itself should manage the conversion, NEVER the file itself, NEVER the working profile. The file should be saved in the working profile that was used to create it. During the printing process there should be a "Soft proofing" step where you can VIEW an image in a different colour space but without the lossy process of converting to the actual colourspace. When this is done at the very end when you print you select the settings used in soft proofing. Done and with no loss of colour fidelity along the way.

The only reason I can think of to convert and save an image in a colour space that reflects a specific CMYK gamut is if your printing company doesn't do colour management and requested you to provide them a file with a very specific gamut to suit their very specific printer. Not unheard of but rare in the Photography world. Quite common in the printing press world though. If this is the case disregard my ramblings.

 

[clanthar]

I'm currently going through the annoying process of converting 20 images to CMYK for printing,

And all my alarm bells went off.

What's your process that requires you to convert images for printing? The printing process itself should manage the conversion, NEVER the file itself, NEVER the working profile. The file should be saved in the working profile that was used to create it. During the printing process there should be a "Soft proofing" step where you can VIEW an image in a different colour space but without the lossy process of converting to the actual colourspace. When this is done at the very end when you print you select the settings used in soft proofing. Done and with no loss of colour fidelity along the way.

The only reason I can think of to convert and save an image in a colour space that reflects a specific CMYK gamut is if your printing company doesn't do colour management and requested you to provide them a file with a very specific gamut to suit their very specific printer. Not unheard of but rare in the Photography world. Quite common in the printing press world though. If this is the case disregard my ramblings.

Yep, my alarm bells went off too -- I'd didn't want to be quite so forceful leaving open the possibility the OP has his own offset press.

BUT if you're converting an RGB photo to CMYK you better be a press technician in one room with a computer connected to the imagesetter in the other room next to the room that has the press in it. Otherwise you're ruining your photo. A photographer should in almost all cases NEVER convert an RGB image to CMYK.

Joe

 

[epatsellis]

I'm currently going through the annoying process of converting 20 images to CMYK for printing,

And all my alarm bells went off.

What's your process that requires you to convert images for printing? The printing process itself should manage the conversion, NEVER the file itself, NEVER the working profile. The file should be saved in the working profile that was used to create it. During the printing process there should be a "Soft proofing" step where you can VIEW an image in a different colour space but without the lossy process of converting to the actual colourspace. When this is done at the very end when you print you select the settings used in soft proofing. Done and with no loss of colour fidelity along the way.

The only reason I can think of to convert and save an image in a colour space that reflects a specific CMYK gamut is if your printing company doesn't do colour management and requested you to provide them a file with a very specific gamut to suit their very specific printer. Not unheard of but rare in the Photography world. Quite common in the printing press world though. If this is the case disregard my ramblings.

Yep, my alarm bells went off too -- I'd didn't want to be quite so forceful leaving open the possibility the OP has his own offset press.

BUT if you're converting an RGB photo to CMYK you better be a press technician in one room with a computer connected to the imagesetter in the other room next to the room that has the press in it. Otherwise you're ruining your photo. A photographer should in almost all cases NEVER convert an RGB image to CMYK.

Joe

Unless, of course, you're designing a document that will be printed by a printer that doesn't color manage and supplies you with either a profile (preferred) or a set of curves to linearize the output (as the printer that prints our school newspaper does) It generally takes a few passes to get a handle on it, but you can get reasonable color images this way, if you're willing to do the work. For some workflows, newspapers being the most prominent, relying on in-RIP RGB to CMYK conversion is fraught with numerous perils, even when everything goes right, all it takes is one pressman having a bad day to muck it up and you have 3-5K copies of crap.

 

[clanthar]

Unless, of course, you're designing a document that will be printed by a printer that doesn't color manage and supplies you with either a profile (preferred) or a set of curves to linearize the output (as the printer that prints our school newspaper does) It generally takes a few passes to get a handle on it, but you can get reasonable color images this way, if you're willing to do the work. For some workflows, newspapers being the most prominent, relying on in-RIP RGB to CMYK conversion is fraught with numerous perils, even when everything goes right, all it takes is one pressman having a bad day to muck it up and you have 3-5K copies of crap.

Like I said above:

Photoshop is capable of managing CMYK images, but that job must be output device specific. There's only CMYK that matches a specific press, plate type, ink and paper combination.

The printer supplied profile you mention references a specific printer ("output device specific") in a room you can go visit where you can see the machine and kick the tires. If this isn't the case then converting to CMYK is a mistake. This is worth emphasizing because I see it done all the time. In the college labs where I work I encounter students all the time printing their converted CMYK files to Epson and Canon 8 color inkjet printers. The result is a disaster and when I investigate and find the CMYK file and ask how that happened they tell me their teacher told them to make it CMYK before they print it -- blind leading the blind.

Joe

 

[Steve01]

Nope, when I asked which is more accurate, I meant viewing a CMYK image in Windows Photo Gallery or in Photoshop?

There are a lot of unanswered questions that could get you more accurate answers.
If the question is what image will look more like the final printed document the answer is Photoshop assuming you are using the correct CMYK profile for the output printer.

If you're printing this at home or sending them to a photolab you should be using a RGB color space not CMYK.
Adobe Photoshop CS5 * About desktop printing

 

[HeyMeester]

View them in PS. Windows doesn't reproduce accurate cmyk.

There is a whole lot more to the final output than just a simple conversion. But for viewing, use PS...