How long does a color by number picture take?
An honest answer instead of a marketing number: region count times seconds per region. Canvas size and apparent complexity are poor predictors, and the useful unit of work is one colour, not one picture.
You want to know whether the picture you have just opened is a fifteen-minute thing or a two-evening thing. Apps rarely say, and when they do the number tends to be optimistic in exactly the direction that makes the picture look approachable.
You can work it out yourself, and the arithmetic is simple enough to do in your head once you know which number to start from.
Region count is the only input that matters
Not canvas size. Not how complicated the artwork looks. Not the number of colours, within reason. The work is one tap per region, so the total is dominated by how many regions there are.
That has a consequence which surprises people. A large bold picture with sixty big regions is much quicker than a small dense mandala with six hundred tiny ones, even though the second occupies less screen and looks less imposing as a thumbnail. Detail costs time; size does not.
If the app shows a region count, or per-colour counts you can add up, use it. If it does not, a decent proxy is to zoom into the busiest part of the picture and count the separate areas in a small square. That local density, extrapolated, is closer to the truth than your impression of the whole.
Building the estimate from the parts
A single region costs you one of two things, plus overhead.
- A tap on a region you have already located: about a second, sometimes less when you are working through a cluster and your hand is already in the right place.
- A tap on a region you have to find first: several seconds, because the search is the expensive part rather than the tap.
- Overhead that is not per-region at all: zooming, panning, switching colours, and the pauses where you sit back and look at what you have done.
A reasonable working average for a mixed picture — some easy clusters, some hunting — is somewhere around two to four seconds per region including overhead. That range is wide on purpose. It is a bracket, not a measurement, and your own figure will settle within a few pictures.
So: three hundred regions at roughly three seconds is about fifteen minutes. Six hundred regions in a dense pattern, where a greater share of taps are searches, is more like forty. A hundred-region picture is under ten. Redo this with your own seconds-per-region rather than trusting these; the reason for showing the calculation is that you can check it.
What pushes the number up
- A small screen. Every small region then needs a zoom or a magnifier, and that overhead lands on a large share of the taps rather than a few of them.
- A palette with several near-identical shades, which adds a decision at every colour change and the occasional wrong-region correction.
- Highly fragmented colours. One colour with two hundred slivers costs far more than two colours with fifty regions each.
- Working in short broken sessions, because every resumption costs re-orientation while you work out where you had got to.
- The tail of each colour. Hunting the last few regions is a fixed tax per colour, and on a dense picture it can be a surprising share of the whole.
The more useful point: the unit is a colour, not a picture
Almost nobody sits down and completes a picture in one continuous stretch, and treating the picture as the unit of work makes the whole thing feel like an obligation with a deadline attached to it.
One colour is a far better unit. It has a clear beginning and a clear end, it takes somewhere between two and ten minutes on most pictures, and finishing one leaves the canvas tidy — every region of that shade is done, so when you come back you are not resuming mid-thought. That is why “finish the colour you are on, then stop” is more useful than any target for the picture as a whole.
It also matches the occasions people actually colour in: a bus journey, a wait, the last part of an evening. A picture that takes forty minutes is not a forty-minute commitment. It is six or eight small ones, and the file sits exactly where you left it in between.
A note on apps that show a timer
Some apps display elapsed time, or an estimate of time remaining. Elapsed time is harmless if you like it and quietly corrosive if you do not, because a visible clock turns a pastime into a performance you can be slow at. An estimate of time remaining is usually region count divided by an assumed rate — the same arithmetic as above with somebody else’s seconds-per-region substituted for yours. If there is a setting to hide either, it is worth knowing where it lives.
Frequently asked questions
How long does an average picture take?
For a typical few-hundred-region picture, somewhere between fifteen and forty-five minutes of actual colouring. The honest way to answer it for a specific picture is region count multiplied by your own seconds-per-region, which settles at around two to four seconds once you have done a few.
Does a bigger canvas take longer?
Not by itself. Time follows the number of regions, not the dimensions of the image, so a large simple picture can finish faster than a small intricate one. A bigger canvas can even be quicker to work, because more screen means less zooming per tap.
Can I stop halfway and come back?
Yes, and it is the normal way to do it. Progress is saved per region, so a picture waits in exactly the state you left it. The one thing that helps is stopping at the end of a colour rather than in the middle of one, which removes the re-orientation cost when you return.
Why do the last few regions of each colour take so long?
Because the easy ones went first, so what remains is the smallest regions in the densest parts of the picture. At a fitted view they may be too small for the display to show at all. Looking for the highlight rather than the number, and zooming into dense areas, is much faster than scanning.
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.