Optimizing images for Google docs likely to be printed June 19, 2013Posted by aquillam in Astronomy.
Time once again for one of those “I’m going to need to do this agan latter so I’d better write it down” posts.
I needed an image for a Google Document that most people will probably print. As anyone who works with both print and web materials knows, this can be a challenge. Monitors usually have a fairly low resolution. The screen I’m woking on is about 114 ppi (that’s pixels per inch). Printers can have resolutions of 1000 or more dpi (that’s dots per inch, which isn’t the same as ppi, but that’s a different post.) Something could look great on my screen and look fuzzy when printed.
So of course, I started by trying a Google search. I tried all sorts of variations on “best format/file types/resolution for images printed from Google Docs/Drive.” My searches kept leading me back to Google Drive support. I found many different versions of how to insert or upload an image, one of which let me know that when inserting an image into a document, “most” file types are supported and the size is limited to 2MB. Thanks Google.
First, I needed to figure out what resolution to use, so I did a couple more searches, and found that the consensus seems to be that, unless you really need something sharp, like a piece of artwork, 300 ppi is pretty good.
I need an image that is the width of the printing on a standard 8.5″ x 11″ sheet of paper. I like using half inch margins, so the printed area will be 7.5″ across. At 300 ppi, a 7.5″ image will be 2250 px wide. For those who like equations, that’s 300 px/in * 7.5 in = 2500 px. Ok, math done, time for the hard part.
I created an image that was a mix of graphical elements and text using Adobe Illustrator with a 7.5″ x 1″ artboard. Out of curiosity, I tried dropping the .ai file into a Google Document. Didn’t work. So I used the Export and Save for web and devices commands to save the image in several formats, resolutions, and color pallets. Here’s what I found.
2250 pixels wide really was the best size. Bigger than that the text became darker but not sharper. Also, the graphics appeared to have an outline, but not a sharp one. Smaller, and everything was a bit fuzzy. The default size when I chose Save for web and devices was 540 px, which was small and fuzzy even on the computer screen. If I were pressed for file size, dropping to 1000 px would be ok.
As one might expect with text, the raster type files were better. The jpgs all seemed to have a faint shadow around the graphics. I could get rid of this by making it a white background instead of transparent, but that made the file bigger and it still didn’t look better than the gifs and pngs.
I had to look pretty hard to find a difference between the png and gif files. The pngs tended to have slightly smoother graphics, maybe. At least I could convince myself of that. However, the gif was a smaller file size.
A couple other notes about the settings in Illustrator. For gifs, using 128 colors and no dither resulted in a better color match (dithering tended to lighten the colors). Setting the optimization to type resulted in clearer text and didn’t degrade the artwork. Using None or Art optimized made the text slightly fuzzy, and really didn’t help the graphics. Of course all of these things could easily change depending on the artwork in question.