How can I prevent pixelation in this process?

[Ziggletooth]

I am new to graphical work and I have just started using GIMP and AI, I have something I want to do but I'm not sure how to do it. I would really appreciate some help.

I want to send some designs to print. I have been using GIMP to create my designs.

I have used assets from the internet in my designs which are raster images.

I have noticed that resizing the images creates pixelation and I'm concerned whether it will appear in print.

I have noticed the assets I've used are 'cartoon like' in the sense that they are opaque distinct colours like clip art. I concluded that I could use Adobe Illustrator to convert the original raster images into vector images and then resize them.

I converted my images into vectors and scaled them to pixel count. It looks perfect in AI.

I've exported this to png but I notice the pixelation returns in the exported file.

As I said before I am new to all this stuff and how everything works so please excuse my lack of knowledge, but can I remove the pixelation and create print quality images?

[Kurt Gold]

Do yourself a favour and try to learn the basics about the difference between raster art and vector art. Then talk to your print provider and ask him what kind of files he prefers to produce the print product. It is unlikely that he wants .png files. That file format is not well-established in real production environments.

You mentioned that right now you are in uncharted waters. That's fine, but take a basic course. Otherwise you may be deeply disappointed all too often.

[Doug A Roberts]

do what kurt suggests of course, but i'm interested in what led you to think you need PNGs?

[Mylenium]

I can only second what the others said - your lack of basic and generic knowledge about workflows and formats is painful to watch/ read. By all means do a bit of reading up. Converting vectorised artwork back to a pixel format should only be done when its required e.g. for use on web pages. It's not impossible to print pixel graphics nicely, of course, but that would necessitate another read-up on DPI/ PPI/ LPI and how it relates to print production and other media uses. In any case, pixel data will always degenerate when extrapolated to larger sizes. Even the smartest resizing algorithms can't avoid that and you guessed it - this opens up a whole new can of worms on these techniques, using Photoshop and all that. Since you already have vector data, the most efficient way to get it to your printer would be to just save a PDF with respective settings, but then again they may just love to have an EPS. In any case, you have to read their exact requirements and check their web site or ring them up. If you are using an online service liek VistaPrint they may in fact accept your PNG just fine, but at the risk of repeating myself, you have to consider that DPI thing. As you see, this is complex and only educating yourself can get you out of this confusion.

Mylenium

[Ziggletooth]

The problem is I want to import it into GIMP but GIMP cant handle vectors which is why I want to convert it into a raster format.

A lot of people are not clear on my thought process here, so I'll explain my actions again. I know that vector art describes graphics using a mathematical formula that's why I thought I could prevent the pixelation that would occur when resizing a raster image by converting it into vector first and resizing that. Is there something wrong with that part?

It sounds like the problem is converting back to a pixel format. I can only assume that's because the sharpness is less than a pixel, causing pixelation during the expansion into a raster image, is this correct? I can only speculate because I don't know anything about graphic design.

* In that case is there not someway I can tell the formula to round to a pixel or something? Wouldn't that produce a pixel perfect PNG?

I'm not doing a graphic design course either, I'm doing a single project by myself as a gift for a friend so I'm more concerned with a practical solution to this problem.

I would like to rephrase my question.

Is there a way I can take a PNG or JPEG raster image of a cartoon and, through some process, use a smaller version of that without pixelation in my GIMP project?

If that is fundamentally impossible, why? and is there some workaround I could do or different order to do things?

In the end I need a JPG, BMP, PNG, GIF or TIFF according to the website.

Any help would be appreciated.

[Kurt Gold]

Thanks for the clarification. That explains your situation.

Now it's time to substantiate some things:

- Elaborate on what you mean by 'pixelation'. Show some screenshots at 100 % zoom level.

- Explain how you have exported the Illustrator documents to .png. What export setting did you use? Please tell in detail and/or show screenshots.

- If possible, provide the original .ai file, so one may take a look at it.

- Which version of Illustrator and Gimp are you using?

[John Mensinger · Accepted solution]

Ziggletooth wrote:

I converted my images into vectors and scaled them to pixel count.

Not sure what you mean by "scaled to pixel count." Using the pixel as a unit of measure can be a slippery slope even when the output intent is on-screen, let a lone when the graphic is destined for print. Use an absolute unit of measure (inches, mm) and size the graphic to the final printed output size.

I've exported this to png but I notice the pixelation returns in the exported file.

Don't use PNG for print, and for that matter, don't export to raster formats from Illustrator; instead, try just copy and paste from Illustrator to a canvas in GIMP. I don't have or run GIMP, so I can't test it, but theoretically, this will rasterize the vector graphic at the resolution already set for the GIMP image/canvas.

In the end I need a JPG, BMP, PNG, GIF or TIFF according to the website.

Sounds like a Zazzle-type requirement. In my experience with that stuff, a TIFF image of relatively high resolution (200ppi+) works well, although if you need a 'transparent' background (typically in a case where you're printing on fabric that's not white), PNG is the only format that will give you that result in their process, provided your PNG has a transparent background. (In other words, TIFF transparency is lost in their process.)

[Ziggletooth]

Thanks I can try a few more things now.

I wish I could just submit a PDF, in that case I could just finish the design in AI, putting the vector graphics in last and exporting to PDF.

Kurt brought up an interesting point. I have been told that the printed product would not appear as sharp as an image you would see on your computer. In other words I am under the assumption that even if I can't see the pixelation at 100% magnification on my computer screen I might still be able to see it blur on a physical product. Is that true?

How can I can tell if a image is too pixelated for print?

My project is to design my friend some custom playing cards. The finished product will be on plastic.

[Nikolai.L]

I agree with John Mensinger's comments, but to add on a bit, when you open up a GIMP file to paste vector art into, make sure that it is set at the correct size in terms of units (inches or millimeters), AND that it is at high resolution (300ppi) is going to be safe for something that's going to print--but the company you are sending to should have that information on their site as well. 

I don't know about GIMP, but in Photoshop, these measurements come up in a dialogue box when you open a new file, or can be found under Image>Image size. So, for example you might have settings which say:
Width: 2in
Height: 3in
Resolution: 300 pixels/inch.

[Ziggletooth]

The copy over method doesn't work, I don't think AI stores the data internally the way it represents it.

For example if I set the size to 700x700 pixels using the transform tool and copy that straight into GIMP the size will not be 700x700 but something bigger.

Still I managed to get something of fair quality, some pixelation is just inevitable when your final product is a raster image.

Thanks all.