Colouring with reading glasses or presbyopia
From the mid-forties the eye focuses less well up close. Holding the phone further away does not help, because the digit shrinks with the distance. Making the target bigger is the only move that works.
The numbers are small, and at some point in your forties they stopped being small-but-fine and became small-and-annoying. You find yourself moving the phone back and forth looking for the spot where it comes clear, and increasingly there is no such spot. This is not the app getting worse, and there is a specific reason the instinctive fix does not work.
What is happening, plainly
The lens inside the eye changes shape to focus at different distances, and its ability to do that declines gradually through adult life. It is usually somewhere in the mid-forties that the near limit moves out past the distance at which people like to hold things, and that is when it becomes noticeable. The name for it is presbyopia. It is an ordinary age change that happens to everybody, not a defect, not a disease, and not a sign that you have damaged your eyes by reading in bad light or looking at screens.
What it means in practice is that there is a nearest distance at which you can focus, it is further away than it used to be, and it keeps moving out for a couple of decades before settling. Reading glasses move it back in.
Why holding the phone further away does not work
The instinct when something is blurry up close is to move it away, and for a page of ordinary text that works for a while, because the print is large enough to survive the loss of angular size. For a colouring app it fails almost immediately, and the reason is arithmetic.
Moving the phone further away does push it towards the distance you can focus at. It also makes everything on it smaller in exactly the same proportion. The digit was near the limit of what you could resolve; now it is past that limit, and it is in focus. You have traded one kind of unreadable for another.
So distance is the wrong lever, and it is the one everybody reaches for. The right lever is size: make the target bigger while keeping the device at a distance you can focus at. That is what zoom does, and it is why zoom deserves to be your normal working mode rather than something you resort to when a region is unusually small.
What actually helps
- Zoom by default. Fit the picture to the screen to see where you are, then work at three or four times that and pan. This costs a few extra drags and removes the entire problem, because a digit at four times its size is not a small target for anyone.
- Turn up the system text size and display zoom. Neither affects the artwork, but both affect the app around it — palette labels, buttons, menus — and those are usually what people are squinting at when they are not on the canvas.
- Choose artwork with larger regions. Region size is a property of the picture, and no setting rescues a lattice of hair-width regions. Look at the thumbnail: if it reads as texture rather than shapes, it will be hard work.
- Put more light on the situation. Bright surroundings make your pupils smaller, and a smaller pupil gives greater depth of focus — the range of distances that look acceptably sharp widens. It is why the same book is easier by a window than in a dim room, and why reading in bed is the hardest case.
- Clean your glasses. This sounds like filler and it is not. A film of skin oil scatters light and reduces contrast across the whole field, and because it builds slowly nobody notices the day it became bad. Clean lenses and a clean screen together are worth more than most settings changes.
The varifocal problem
If you wear varifocals or bifocals, there is a specific geometry problem with a handheld device that is worth knowing about, because it produces a very particular kind of frustration.
The near-vision part of a varifocal lens is at the bottom. It is designed for reading something held low and in front of you, and to use it you tilt your head back slightly and look down through the lower part of the lens. That works for a book on a table. With a phone held low in your lap, you are already looking steeply downwards, so you may be looking through the bottom edge of the lens or past it entirely, and the sharp zone is narrow from side to side as well, which is why the picture goes soft when you look to the left or right of centre without turning your head.
Two adjustments. Bring the device up towards chest or chin height rather than resting it in your lap, so you are looking through the reading zone rather than under it. And move your head rather than your eyes when you want to look at a different part of the picture, keeping the sharp corridor pointed where you are working. Both feel unnatural for a day and then become automatic.
When it is not just presbyopia
Presbyopia comes on gradually over years. It is symmetrical, it affects near vision specifically, and reading glasses fix it. Anything that does not fit that description is worth an appointment rather than a workaround.
- A sudden change in near vision, or a change over weeks rather than years.
- One eye clearly worse than the other, or double vision.
- Persistent eye pain, or headaches that recur with close work and do not settle.
- Reading glasses that used to work and now do not — prescriptions drift, and an out-of-date pair makes everything harder while feeling like it should be fine.
Most of that is routine, which is the point: an optometrist can sort it out quickly. Adjusting a colouring app to work around a vision change only postpones the thing that would actually fix it.
Frequently asked questions
Why does holding the phone further away not make the numbers readable?
Because moving it away shrinks the digit at the same rate as it improves the focus. You end up with a sharply focused character that is now too small to resolve. The fix is to make the target bigger at a distance you can already focus at, which means zooming.
Is presbyopia a problem with my eyes?
It is an ordinary age change that happens to everyone, usually becoming noticeable in the mid-forties, as the lens becomes less able to change shape for close focus. It is not caused by screens or by reading in poor light, and reading glasses correct it.
Why is it easier to read the numbers in a bright room?
Bright surroundings make your pupils smaller, and a smaller pupil increases depth of focus, so a wider range of distances looks acceptably sharp. That is why the same picture is easier by a window than in a dim bedroom, and why reading in bed is the hardest case.
I wear varifocals and the picture keeps going soft — why?
The reading zone of a varifocal is at the bottom of the lens and is narrow from side to side. A device held low in your lap means looking under that zone rather than through it. Raising the device towards chest height and turning your head rather than your eyes usually fixes it.
Try it on a real canvas
Numbrush is colour by number for adults: mandalas, rose windows and geometric pattern work, twelve colours a picture, a magnifier for the tight spots, and a wrong tap that costs you nothing. Free, offline, no ads and no account.