Before we can even start a digital painting,
we get hit with a choice: what size is this picture going to be? There are three main things to
deal with: the number of pixels, the physical dimensions for printing, and the number of
pixels printed per inch. What you do with those depends on what the art is for: whether
your art is meant to be seen on screens, whether it’s for printing, or whether it’s meant
to be just for fun or practice and you don’t know if it’s going to be printed or not, you
just want to get started and you need a size to work with and you don’t want to just pull
a bunch of random numbers out of your head in case that turns out to be a really bad
idea. Let’s begin by looking at a picture in different sizes, just to start getting
a feel for what it looks like in practice. This one is 8900 pixels by 6500. In screen
terms it’s easily bigger than 8K Ultra HD. It can print out at about 29 inches or 75
centimetres across at high quality, or double that at decent quality. In camera terms it’s
about 58 megapixels. Now let’s halve the dimensions to get a quarter of the number of pixels.
4450 by 3250. This is larger than 4K Ultra HD. Print size will be about 15 inches or
37 centimetres across at high quality. As a photo it would be a bit over14 megapixels.
Let’s shrink it by the same percentage again, to 2225 pixels by 1625. Full HD fits inside
this fairly easily. The picture could print at about 7.5 inches or 19 centimetres across
at high quality, and it’s roughly 3.5 megapixels. And down again one more time, to only 1113
by 813 pixels. While this is pretty tiny, it’s still a lot bigger than DVD resolution.
At high quality it would print out at less than 4 inches or 10 centimetres across, which
is okay for a birthday card or a photo album print, and it’s just under 1 megapixel. Let’s
get down to details. If your art is meant to be seen on a screen, it’s pretty simple:
all you need to know is the number of pixels on the screen your art is inteded for. If
it’s Full HD, you can type in “1920” pixels wide and “1080” pixels high, then just ignore
the rest of the numbers, click “OK”, and start painting on a Full HD image. If your art is
to be printed, things get a bit trickier, but not too much. Your software may even have
presets that do the work for you. For example, if you want to print on US Letter paper, you
might be able to just pick that preset and it will put the physical dimensions in automatically.
Otherwise you can just measure the paper or look up the info online, and type the details
in yourself, making sure to see if you’re typing in inches, centimetres, or millimetres.
However, these measurements only tell the computer the physical size of the final print,
not the quality. That’s where the pixels per inch part comes in. This tells the printer
how many pixels to print per inch. The more pixels there are, the higher the potential
for quality and detail. This can be pretty much any number, depending on the printer’s
limitations, but there are a couple of common ones we can start with. For high quality printing,
300 pixels per inch is a good one. For decent quality, try 150. For screens, two common
numbers are 72 and 96, but it doesn’t actually matter, it only really matters for print.
You can actually change this number later on. For example, I can load up a picture which
is 300 pixels per inch, click “Image Size”, make sure the image doesn’t change when I
change the pixels per inch, then type in 150. The actual picture hasn’t changed at all;
it’s exactly the same number of pixels, but those pixels will now print out at a larger
size. This means you’ve got some options, even after you’ve finished your image, but
it doesn’t mean you can start with a small image and magically make it bigger later on
without losing any quality. In that way it’s no different from blowing up a photo. If you
want to print it big, start big. In fact, I recommend working larger than you need to
so you’ve got more room to move later on. In that case, adding more pixels or centimetres
when starting your image might be a good idea. You can always crop or shrink the artwork
back down later on. If you’re printing, having a little extra room also means that you can
trim the edges down to the right size and not worry about having little strips of white.
By the way, the tools I’m using here should have equivalents in most worthwhile digital
painting software. For example, instead of “Image Size” like I’ve got here in my old
version of Photoshop, Krita has “Scale Image to New Size” and “Clip Studio Paint” has “Change
Image Resolution”, although some of the details may be different. Now for the paintings with
unknown purposes. I suggest a starting point of 4530 by 2800 pixels. You can go bigger
or smaller, wider or taller, or whatever you like. It’s just a starting point that you
can completely change, but here is why I’m suggesting it: first, it’s a bit bigger than
4K Ultra HD, so it’s good for a lot of screens. It’s also bigger than A4 or US Letter paper
when printed at 300 pixels per inch, so it’s good for a lot of print stuff as well. In
camera terms it’s about 12 megapixels, just in case that helps you visualise it, and the
overall image proportions are based on the so-called “Golden Ratio”, which might be useful
for some people. It’s really up to you, and the more pictures you paint, the more you’ll
figure out what suits you best in your journey of making good-looking art.