Exporting to PNG as CMYK

[jughead77a]

I have been trying to save my images to print so I can sell them on my Etsy shop.

First I copy and paste from Illustrator into Photoshop onto the canvas (8x10 inches / 2400x3000 pixels at 300ppi) as a vector smart object. Then I flatten or merge all the layers then go to Layer > Export as > PNG.

After I saved it I open the document again. I check the ppi which is now at 72ppi and the inches have changed to 33 x 41 inches but the pixels remain the same!! wtf?

This is so confusing to me. Can someone tell me what I'm doing wrong?

[c.pfaffenbichler]

Providing fine data as png is not a proper choice, also as it does not support CMYK. 

And why would you provide CMYK images in the first place? Are you sure you know the actual print conditions? 

You seem to get hung up on an irrelevant factor here – the resolution is not relevant if you cannot be absolutely sure about the final print size; what matters are the pixel dimensions. Will they provide for a sufficient resolution at plausible output sizes? 

8x10 inches at 300ppi or 33,333x41,667 inches at 72ppi does not really make the image better or worse. 

And why do you not export a pixel image from Illustrator straight away? 

[jughead77a]

It has to be CMYK. for print physical art prints, not RGB or the colors wouldn't come out right.

I was just confused as to why it's giving me different sizes in inches after I saved the image.

I can't figure out how to save a file in illustrator at 8x10 inches in high res CMYK.

[c.pfaffenbichler]

»It has to be CMYK. for print physical art prints, not RGB or the colors wouldn't come out right.«

There isn’t just one CMYK Color Space, there are many CMYK Color Spaces, providing an image in the wrong CMYK Space is in general worse than providing it as a profiled RGB image. 

[Mylenium]

I concur with Mr. Pfaffenbichler. Exporting to CMYK is useless. Such a workflow would mandate proper color management, calibrated monitors, profiled printers - none of which is relevant or known to average customers. All they may want is to print your graphics on their home printer using its default settings, which will simply assume standardized sRGB data funneled your operating system's print engine. The same applies to the resolutions stuff als already explained. Should professional commercial printers want to license and use your work, I'm sure they'll contact you and request editable source files for the right price, so no point to bother with convoluted procedures for now.

Mylenium

[jughead77a]

But what if I was printing it at home myself from my own printer as well? Would CYMK still be useless then? It would be ok just using RBG? I plan on using a Canon Pro 10s.

[davescm]

CMYK is wrong to use with that printer. The printer driver on your Canon expects RGB data. It needs this as the conversion is not to 4 colour inks but to all the inks in the printer and the driver is designed to make that conversion.

Dave

[D Fosse]

Think about it. That printer uses 10 inks, not 4. So CMYK doesn't make any sense.

[Test Screen Name]

I agree that CMYK is certainly the wrong thing for something sold for printing by ordinary customers. If you were making it for a print shop, with a known CMYK press and inks, it might be practical. But the really big thing here - and someone has mentioned it but you may not have picked this up - you cannot save a CMYK PNG file, because there is NO SUCH THING. 

[jughead77a]

I am able to export it as PNG and still keep the CMYK setting. But not save as you said.

[Test Screen Name]

No, you are NOT able to export a CMYK PNG, because there is no such thing. But, because Export is a web-only function (yes, it's a stupid name for a web only function), it automatically converts everything to RGB and throws away the resolution, because that's what is needed for the web. So, you have CMYK and you export PNG - you get a PNG, and it's CMYK, and it's not got a ppi value (which you see as "72" because that's the default). 

[davescm]

Hi

You have some basics to learn.

1. 1. There is no generic CMYK. There are specific CMYK profiles based on the output press. It is important to use the right one.  Converting between CMYK profiles is not a good idea. Note I said output press. If the output is to be inkjet then the document should be RGB. Inkjet drivers expect RGB data.

2. Export functions are designed for Web use. As such they strip out the PPI value, which is just that - a number held in the file. The purpose of that number is to tell a print driver how many image pixels to print in a given area and hence how big the physical print will be. For web use, displayed on a screen, that PPI value is irrelevant and is removed. When you open a document with no PPI value, Photoshop assigns 72 PPI as a default. This is only do it can show you a print size. So the change you saw from 300 PPI to 72 PPI was caused by export removing the irrelevant PPI value altogether. As you correctly say the image pixels are unchanged.

3. PNG may or may not be the best format. For graphics, it can work well and it does support transparency. For photographic images, with no transparency, jpeg is a better format and usually results in smaller file sizes.

Dave

[davescm]

One more thing. It is important when exporting an image to embed the colour profile. So when you do export check both convert to sRGB and Embed Color profile. That way, those using colour managed systems will see your images as you intended. 

Dave

[jughead77a]

Thank you for explaining this. Though it's a bit confusing to me because if you look for a tutorial on printing art prints the ones I've seen say to only use RGB for web graphics and always CYMK for print. Otherwise the colors wouldn't come out right. Is this incorrect? and yes when I Export there is always a checkbox checked that says "convert to sRGB" which is always checked.

[davescm]

If you are producing artwork for a specific printing press then there is an argument for working in the CMYK profile specific to that press. Inkjet printer drivers are designed for RGB data.

For general art though, or if the final output is not known, then working in RGB is safer. It can be converted to CMYK later if it is to be printed on a press.

On thing to be aware of with artwork, it also applies to photographs but is usually in smaller areas than painted graphics. When you come to print there may be colours that cannot be printed on that printer. These are called out of gamut colours. You can check for these by soft proofing to your output printer and paper profile. Then adjust those areas so they look acceptable within the range of colours that your printer can print. That is why using the correct printer and paper profile is also important, it will ensure Photoshop uses  the full capability of your printer.

Dave

[jughead77a]

Thank you this was very helpful. I am beginning to understand better now. So every printer is not equipped to use the CMYK profile so it's best just to use RGB color mode. The default color profile I get in Photoshop is Working RGB: sRGB IEC61966-2.1 is this acceptable to use? Can I also ask when saving in Illustrator what color profile is used? RGB as well?

[jughead77a]

How do you check Embed Colour Profile?

[Test Screen Name]

"How do you check Embed Colour Profile?" It's an option in SAVE AS. Ignore, as we have said, EXPORT. There's another puzzle here - you have an Illustrator design, why do you even involve Photoshop? Are you doing post production editing on it?

[davescm]

Hi

So every printer is not equipped to use the CMYK profile so it's best just to use RGB color mode.

It is not just a case of not equipped, your inkjet printer with multiple inks can print colours that cannot be described in a simple CMYK model. So make your documents in RGB then the driver will convert them to the coloured inks.

The default color profile I get in Photoshop is Working RGB: sRGB IEC61966-2.1 is this acceptable to use?

Acceptable , yes. However Adobe RGB1998 can contain more colours that can be printed by your printer, so I would use that.  When sending to the web though, always convert to sRGB and embed the profile. Although sRGB has a more restricted colour gamut, it is safer to send and view on websites.

How do you check Embed Colour Profile?

In the Export As dialogue (if you are using Save for web the same boxes are there) :

Note, the above is for exporting to the web. When saving your master document, don't convert to sRGB. Just save it in the profile you are using (e.g. Adobe RGB1998) and make sure the embed profile check box is checked when saving (it will be by default). I would always save the master as a PSD/PSB or TIFF complete with layers etc.

Dave

[davescm]

Don't just check - Convert to sRGB. Also check - Embed Colour Profile.

Dave

[c.pfaffenbichler]

And to reiterate: When providing RGB images they should have their profiles embedded. 

[davescm]

Good point Chris. I was typing my second reply above as you posted this.

Dave

[NB, colourmanagement]

Only printers driven by RIP software can take CMYK right through the process. The "normal" inkjet printer driver software uses the "Quickdraw pipeline" so it's purely RGB based.

IF you send a CMYK file through that process it is first converted to RGB then the driver works out how to use the multiple inks to print it. So making CMYK in this instance is a mistake.

As others have written, forget EXPORT its for web use. 

Use "save as" and make sure you check "embed profile" 

It can be preferable to send out images in the sRGB colour space to users who may know little about colourmanagement, it's safer. But if your originals are in a larger colour space, such as Adobe RGB* then save (archive) the Adobe RGB original as TIF or PSD and make a copy - convert this to sRGB, resize***, save as a JPEG** and send out to your customer. 

(*Adobe RGB is a larger volume colour space, so capable of "containing" more saturated colours)

(**Forget PNG, Jpeg is a standard compressed format for print files.)

(***I'd decide on a print size - say it's A4 and resize the image to 300ppi at A4.

(or 240 or 360 ppi [edited] if its for an Epson printer only))

72ppi is only suitable for a file to be used onscreen - it's a display screen resolution.

Read about ICC profiles and colour spaces here: 

here is some reading on ICC profiles and how they work for you to provide accurate colour through the digital workflow: https://www.colourmanagement.net/advice/about-icc-colour-profiles/

I hope this helps

if so, please "like" my reply

thanks

neil barstow, colourmanagement.net :: adobe forum volunteer

[please do not use the reply button on a message in the thread, only use the one at the top of the page, to maintain the thread title and the chronological order]

[davescm]

72ppi is only suitable for a file to be used onscreen - it's a display screen resolution.

Just for clarity ( I realise you know this Neil but for other users reading through the thread), the document ppi is irrelevant for screen use. It is used for calculating the size the document will print.. What matters for on screen use is the dimensions in pixels - that is it.

One place the display screen resolution can be entered is in Photoshop's preferences, where it is used along with the document ppi to calculate the on screen size when using "View >Print Size", but in reality there are few screens these days which only have 72ppi. Most are higher and some much higher.

*I'd decide on a print size - say it's A4 and resize the image to 300ppi at A4.

(or 240 or 260 ppi if its for an Epson printer only))

The Epson drivers do not scale at 360 ppi - so if you want to control the scaling algorithm in Photoshop and avoid the driver scaling then use 360 ppi (or 720 ppi) on Epsons. You can prove this through testing, as I have done with test patterns on my Epsons, although with real world images you would be hard pressed to see a difference.

Dave

[NB, colourmanagement]

Dave,

You're right - thanks for explaining further about screen rez. Mine was oversimplified. 

Also for spotting my Epson printer ideal resolution typo error, I meant 240 or 360 (not 260!)

I did some rather extensive testing with tech head Joseph Holmes https://www.josephholmes.com many years ago which settled the argument for me about Epson driver scaling once and for all, you're right that an integer of the native resolution: 720 is superior

SO - 360, 240 and even 180 gave far sharper thin lines than 300ppi

I love Joseph's work on ICC working space profiles: https://www.josephholmes.com/profiles/about-my-profiles - so enabling once grasped

Neil B