The easiest way to convert my image to 300 dpi and CMYK with Photoshop

[Mañana]

Hello, i have a image which i need to convert to 300 dpi and CMYK, i have photoshop but don't know how to convert it.

So, what is the easiest way to convert my image using Photoshop?

[D Fosse]

First ask the printer which specific CMYK profile to use. There is no such thing as a generic CMYK. Then Edit > Convert to Profile.

A quicker way is Image > Mode - but note that this directly converts to whatever you have as Working CMYK under Color Settings.

Photoshop out of the box comes with US Web Coated (SWOP) as working CMYK. This may well not be the right one, especially if you're outside North/South America. Then it's guaranteed to be wrong.

Resolution is given as ppi (not dpi). It means pixels per inch, and this simple calculation determines a physical print size for the pixels you have available in the file. Put another way, it determines how big each pixel will print on paper and thus how much the pixels are spread out.

So what you do is open Image  > Image Size. Keep "resample image" unchecked !, you don't want your file changed. Put 300 in the resolution field. Depending on how many pixels you have in the file, a physical print size is calculated from that. If you have enough pixels in the file, the size will be at or above the required print size. The you can just click OK, and this will be added to the file's metadata and the file printed accordingly.

If you don't, it's back to the drawing board.

[Mañana]

The site which i will order from just says that the image have to be in 300 dpi or more and in CMYK, i asked about CMYK-profile, but they just sayd that CMYK will be fine.. The site is based in US but the printing is based in Hongkong.

However, my image is in black and white, so the only colour that will be used for the printing is black.

Does the cmyk-profile matter when printing in single colour/black?

[D Fosse]

Mañana  wrote

However, my image is in black and white, so the only colour that will be used for the printing is black.

Does the cmyk-profile matter when printing in single colour/black?

Well, it depends. There may be differences in dot gain, so you may get tonal shifts.

Do you plan to submit the file as 0-0-0-K (a CMYK file with empty CMY)? That's often the safest way.

If they just throw a blank stare when you inquire about CMYK profile, you clearly shouldn't expect any kind of accuracy anyway. I'd go elsewhere.

[Test Screen Name]

If the image resolution is too low, Photoshop can't fix it. That would need sorcery. But what matters is the EFFECTIVE resolution, not just the ppi in the file. If you're not sure about the actual effective resolution please let us know the size in pixels and the suze you need to run it at (in inches or mm).

[Mañana]

the image is in 1181x1181 px.

I read btw that 1181x1181 px is the right dimension for 300dpi, but when i view the image properties it says 72dpi.

[Mañana]

I forgot to mention, my stickers will be 10x10cm.

[D Fosse]

It should be noted that 0-0-0-K usually gives rather poor black levels. For that, you need all four plates.

You might want to look at this thread: https://forums.adobe.com/thread/2309803

[shumicse]

I dont know will it help you or not but you can try this website Online RGB to CMYK conversion  for the conversion.

[D Fosse]

Well, that's one of the better ones - it does ask which particular CMYK profile you want - but this is for people who don't have Photoshop. If you do there's no point.

[shumicse]

Yeah I got your point. As you have already mentioned a process so I was just giving another option which may help.

[Test Screen Name]

The resolution and the size are set separately. It's simple arithmetic though.

300 ppi (same as dpi) is 300 pixels per inch.

1181 pixels, with 300 pixels in each inch, means there is 1181 / 300 inches. That is 3.94 inches, both width and height.

So, if your image is to print printed at just under 4 inches, it is the perfect number of pixels, and you can change it to 300 ppi. If you want to print it bigger than this, your image is not suitable. If you want to print it smaller, we can make it work.

[Mañana]

i have convert my picture to 300 dpi now, the picure got bad compressions artifacts at the white area along the black lines. Since i only will print in one colour, i don't know if it will matter..

[Mañana]

the picture is 4921x4921 px now btw.

horizental resolution: 300 dpi

vertical resolution: 300 dpi

[Djuna_A_]

MVP, you said that ppi is the same as dpi in Photoshop CC 2017?  is that right? I thought dpi was a printer's setting, for the ink dots, and ppi was a pixel setting, for on-screen viewing.  If my printer is requiring 350 dpi, do I set the ppi to 350? 

[Test Screen Name]

I was just recognising that many people use ppi and dpi interchangeably. Clearly the original poster used it to mean image resolution. I chose to reply "ppi (dpi)" to acknowledge the original poster's question.

If your printer (person or company who runs a printer) says they want 350 dpi in your files, this means that they want 350 ppi.

If they ask what dpi you want, and aren't offering to make files for you, they are asking which printer resolution you want.

It's pretty unambiguous, but nevertheless people do get rather worked up if you use the "wrong" one.

[Julia274733689n7h]

300 dpi isn't the same as 300 ppi that's a mistake many make 

[Test Screen Name]

No, you did something very wrong. You increased the resolution (we can tell because you have more pixels). Do NOT do that! In image size, turn off resampling and you will change the ppi only Without affecting image quality.

Your original size, 3.94 inches, was exactly 100mm, so it was perfect before you changed it. GO BACK TO THE UNEDITED VERSION, don't reduce the file you increased.

[Mañana]

Okay, i have the original file saved so it's cool. But is the original file at 1181x1181px really in 300 dpi? Since the horizental and vertical resolution says 72 dpi?

I can't use photoshop right now btw..

[Test Screen Name]

No it isn't at 300 ppi (dpi). its 72 ppi. But that's cool. If you need to change it use Image Size as I said: no resample.

[Mañana]

I'm on photoshop right now and going to save the image to CMYK. Which profile should i use for generic black colour printing? (Based in US/hongkong)

[Test Screen Name]

Ask the printer. Printing is not a generic process.

Is this printing in black and white on a 4 colour page, or is it a black and white print run using only black ink? This is extremely important too - if you use a profile meant for colour printing on a black only page, you will get washed out greys.