Hi, I'm new to using to Krita. I want to draw pictures as cmyk so I can upload them to print on demand sites like red bubble. If it matters, I was planning on starting with products like stickers.

I'm nor sure if I'm doing this right but I start a new document and for mode I choose cmyk/alpha. The profile is on the default "chemical proof", depth set to default "8 bit integer/channel, and space browser by default. I don't really know if any of those settings are correct.

After drawing something I save it as a Krita document. When I am done I export it as a PNG. When I do this a pop up comes up with the options "save as indexed PNG, if possible", "Force convert to sRGB", and "Store alpha channel (transparency)" already ticked. Since I want this in cmyk should I unclick the "Force convert to sRGB" option?

While I'm on the topic of cmyk I have another question. Another print on demand site society6 says "Before uploading, please make sure that your files are saved in RGB and not CMYK. Files uploaded in CMYK will render with inverted color." This is the opposite of red bubble which was saying cmyk. From my understanding printed products are supposed to be in cmyk. So for society 6 do you think they mean I should use colors that would fit Cmyk but to save as a RGB file?

Thanks for any input. Looking forward to learning to use Krita

a) PNG does not support CMYK, so that will always be converted to RGB.
b) This is a really big topic. I could try to rewrite what's in the manual on this topic, but that wouldn't be clearer, so just check out https://docs.krita.org/en/general_conce ... kflow.html

In general, only use cmyk if your printer tells you to and provides you with a cmyk profile to use. Most don't, these days.

If you try to Export a CMYKA image as a .png file, you HAVE TO tick the 'force convert' box or it will report an internal error (non-crashy) with no explanation of why it does this. That is the behaviour with the latest 4.2.0 pre-alpha appimage.

(I realise that it's mostly a pointless exercise to do that but I thought I'd mention it.)

Thanks for the timely replies.

I was searching for where Red Bubble said they wanted PNG and Cmyk, but I found it was clarified in blog post of theirs

These possible color shifts are why it’s recommended to create your designs in the CMYK colorspace. It’s true that CMYK is a bit more limited, and the colors may often look flatter than RGB, but accuracy is the main benefit. If you create your new designs in CMYK, there should be no dramatic shifts when you export your designs as PNG (which can only be RGB), and then back to CMYK during the physical printing process. Getting in the habit of starting your new designs and illustrations in CMYK, and saving them as your master files, allows you more control over your designs and ultimately less work in the long run.

So these means I should just use Krita in the way I described before(just understanding I'm using it as a color space and not actually saving in Cmyk)? I'm guessing since it would automatically be saved as RGB this answers my question for society6 too. Thanks for the replies.

Red Bubble is very, very wrong. They're not the only ones who spread this bit of wrong information, but it's still wrong. Create your image in RGBA. Use the CMYK profile your printer has given you as the proofing profile: that will keep your image within the bounds of the cmyk colorspace. If the printer really needs a cmyk image, flatten, then convert to cmyk with the right profile and export as tiff. Always keep your project saved as .kra!

[quote="ahabgreybeard"]If you try to Export a CMYKA image as a .png file, you HAVE TO tick the 'force convert' box or it will report an internal error (non-crashy) with no explanation of why it does this. That is the behaviour with the latest 4.2.0 pre-alpha appimage./quote]

Yes, I get that assert as well. It's definitely a bug that needs fixing. Some of the logic here is wrong. See https://bugs.kde.org/show_bug.cgi?id=398241

Thanks for the replies, but I'm still finding this very confusing. Probably is because I don't know much about graphic design. Probably messing with things I'm not ready for yet.

So far the best explanation I've found on Red Bubble is this. I know you already read this but I'm posting ti again to show how the information I'm being given is limited. If necessary I'll have to try contacting them for more specifics.

These possible color shifts are why it’s recommended to create your designs in the CMYK colorspace. It’s true that CMYK is a bit more limited, and the colors may often look flatter than RGB, but accuracy is the main benefit. If you create your new designs in CMYK, there should be no dramatic shifts when you export your designs as PNG (which can only be RGB), and then back to CMYK during the physical printing process. Getting in the habit of starting your new designs and illustrations in CMYK, and saving them as your master files, allows you more control over your designs and ultimately less work in the long run.

I haven't seen anything about a specific cmyk profile, but I'll search more and ask later. Not sure how to set up the proofing profile anyway. I'll have to look more into Krita tutorials later. I remember red bubble specifying PNG so not sure if they'll accept tiff.

I'm tempted to just draw something in cmyk/alpha and then export to png with the forced sRGB and see how it goes. Not sure if that would be unwise.

I'm tempted to just draw something in cmyk/alpha and then export to png with the forced sRGB and see how it goes. Not sure if that would be unwise.

That would work but it would get you into the bad habit of a workflow that is limited and targeted at one particular printing company.

The recommendations from Red Bubble do actually make sense (from their point of view) and seem to be a way of accommodating casual and 'non-professional' customers who are totally unaware of the RGB/CMYK differences and the consequences of printing designs that have been made on a computer by casual users.

They are saying that if you do your work in CMYK then you will not be surprised or disappointed (and not make complaints) about the printed results. If you work in RGB and do soft proofing in krita, or if you do a final CMYK conversion check for visual appearance, then you will be aware of the printed limitations.

As for a specific CMYK profile for printing, this is something that the casual user would not be aware of and might have difficulty in setting up. If you ask, the printing company might provide one, in which case you can use it. This would usually be done by people who produce illustrations, photos and detailed graphic art where exact colour fidelity is required in the printed output with no surprises or disappointments or resulting waste of time and money.

I suspect that any differences between the printer's CMYK profile and the krita default CMYK profile would not be large enough to cause you any surprises or disappointments when producing work for use on printed stickers.

Thanks for the reply. I'll probably try the more casual way to start because worrying about this has been holding me up on the actual creating part. I'll look more into what you said for the future for in case I decide to buy from a printer instead of going with print on demand. I know the print on demand companies take a huge cut but for now I don't want to buy a bunch of stickers, etc in bulk.