How small can/should a vector go? How to tell if it's too small to print
October 31, 2020 10:42 PM   Subscribe

Everyone's always on about how you can enlarge vectors endlessly without losing quality. But what about shrinking them. If I have a fairly detailed vector of say a wreath and then I shrink it down to put on the door of a house that's in the background, is this going to print like a muddled ugly mess?

I have artboards that are 12x12 and 300 dpi. I THINK the printer prints at 150 DPI. Is there some sort of "View it at 50% or 25% or whatever and that's about how detailed it will print rule of thumb?

Alternatively, is there a way I can pick individual objects on illustrator and know how big they are, assuming I print the artboard at a particular size and resolution? If I figure this out and I zoom the image in/out so that the object is the same size on screen as it would be printed, will that tell me how it will look?

I understand it won't be possible to make out all the detail, but I'm worried that say and algorithm will pick out a yellow pixel from a bed, a blue bulb, a green wreath and just sort of print a jumble of coloured pixels and you can't tell it was supposed to be a wreath. In that case, I would obviously be better off to just put a green circle and it will look like a blurry tiny wreath instead of a blurry tiny mess of colours.

Am I just completely wrong to be worried about this?
posted by If only I had a penguin... to Media & Arts (10 answers total)
 
If I figure this out and I zoom the image in/out so that the object is the same size on screen as it would be printed, will that tell me how it will look?

The way I always deal with this kind of thing is doing a render to a PNG image at the same size and DPI that I'm proposing to print to, then opening the PNG in a photo viewer or editor that will let me zoom it without smoothing, then zooming in and out on a region of interest to see how the render has worked out (I use GIMP for the viewing/zooming part but I'm sure Photoshop can do it too). Generally a render to a PNG will be very close, pixel for pixel, to a printed render.

I THINK the printer prints at 150 DPI.

That strikes me as very surprisingly coarse. I'd check that.
posted by flabdablet at 11:58 PM on October 31, 2020 [4 favorites]


By the way, the reason to prefer a zoom that does no smoothing is to make it super obvious when I've zoomed in far enough to be looking at the render's individual pixels. Smoothed zooms usually do too good a job at disguising the pixellated chunkiness I'm actually looking for.

And if I find myself zooming in further and further and not seeing either pixellation or blurriness, that's my cue to realize that a brain fart has got me zooming the wrong window and still looking at the vector original, not the PNG render.
posted by flabdablet at 12:12 AM on November 1, 2020 [1 favorite]


Also beware the your outlines are set to shrink when size changes, other wise you may end up with a scribble with bunch of sharp edges.
posted by b33j at 1:29 AM on November 1, 2020 [2 favorites]


What app are you printing from? If you're working in something like Illustrator, that "300dpi" resolution is generally for raster effects, like drop shadows, glows, gradations, and the like. Vectors are resolution independent.

Technically, you can shrink a vector drawing infinitely. But, in practice, if you shrink a vector piece too far, you will run into issues with vanishing/overlapping points, especially in highly-detailed vector illustrations, like a wreath. You might have to have the app simplify the paths if you're shrinking it too far.

Even most home inkjets print at a higher dpi than 150. 300dpi is pretty standard for color prints on home printers. If it's a highly-detailed illustration (i.e. tons of control points) your home printer might slow a bit doing the conversion on-the-fly.
posted by Thorzdad at 4:01 AM on November 1, 2020


Response by poster: Thanks all.

To save myself some time, do you think I can render from indesign to PDF? that way I could render the whole thing at once into one document instead of having to do each page?

The ultimate printing will be done by blurb (i.e. self-publishing) and yes, the probably print at 300DPI. I was thinking 150 because it is the minimum resolution that they take.
posted by If only I had a penguin... at 7:26 PM on November 1, 2020


Best answer: Rendering source material with vector content as PDF has a pretty high chance of making a PDF that still has vector content inside. So yes, you can surely do that, but it's not going to tell you much about how a raster-rendered version such as a print job will end up looking; you're just moving the render-to-raster step out of your design software's printing function into your PDF viewer's display/printing function.

In your shoes I'd be doing an image render to PNG of at least the image containing the wreath you're wondering about, just so you get an idea of how it comes out. You might even find that doing this gives you the confidence to just trust the rendering pipeline to do the right thing with the rest of the work.
posted by flabdablet at 2:15 AM on November 2, 2020


Best answer: they probably print at 300DPI

Seriously, check this. Even some of today's really really cheap home inkjet photo printers claim 1200x2400dpi. Any professional outfit should be able to give you an actual number for their print resolution instead of just a guess.
posted by flabdablet at 2:16 AM on November 2, 2020 [2 favorites]


To expand on b33j: Illustrator, the vector software I'm familiar with for example, has a button when you're choosing details of your vectors that allows the thickness of the vector to change as the size of the object changes. If this is not chosen, shrinking the vector will leave the lines at their original size. If checked, a .4 mm thick line will become a .2 mm line if the drawing is reduced by 50%. If not, it will remain a .4 mm line...or whatever. If you visualize this, not checking it would make a mess if your resize the drawing.

The converse is true as well. If you allow the vector to change thickness when the drawing is resized and you make the drawing larger, the vector line will also get thicker. Sometimes you may not want that.
posted by tmdonahue at 5:37 AM on November 2, 2020 [1 favorite]


Response by poster: Thanks again, all. Ok, i'll confirm print resolution with blurb.

And yes, I know about vectors shrinking or not the stroke widths proportionately. Unfortunately, Illustrator's setting for this is "strokes and effects". I want the strokes to shrink proportionately but not the effects -- I want my drop shadows of constant size. This is a PITA where I have to get each element sized and in place before applying the drop shadow if it has any strokes (because I need to scale and place with the setting turned on that scales the strokes and effects). And then once it's scaled I apply the drop shadow. If I rescale I have to remove dropshadow, rescale, and then re-apply dropshadow. Anyway, fortunately, I don't really have many elements with strokes. I made some pattern brushes for bead garlands and Christmas lights though, and I need those to rescale not just stay giant.

The wreath is just an example... There are lots and lots of elements that I make big and then shrink down, or are a major part of one picture (so I make it detailed), but then a small background detail in another, so I just paste it over and shrink it down.
posted by If only I had a penguin... at 11:40 AM on November 2, 2020


It's not a matter of the DPI of the printer. It's a matter of how much the printer dots bleed - something that's hard enough to quantify that proofs were invented (I kid).

Want to know the best it could possibly look? Render it equivalently on the screen with the smallest pixels you have access to. My 27", 4k monitor is 163 dpi.

As far as printing at 1200x2400, that droplets of ink, not pixels, although no one will admit it. A particular pixel, printed, will have many of these droplets for every ink color appropriate to that pixel.

Most photographers assume anything greater than 300 dpi is wasted. I have printed photos from an 8 MP camera out to 40"x40" (with help from some rather esoteric up-rez techniques) with no complaints.
posted by notsnot at 6:51 PM on November 3, 2020


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