NotanIzer

Review by eFreeware

NotanIzer is an art and design app from the developer bigpantsgroup, sold for $1.99 with no ads and no in-app purchases. It takes its name from nōtan, a Japanese approach to composition built on the arrangement of light and dark shapes, the same idea the Yin Yang symbol draws on. The app's job is to show you those shapes in a picture you already have.

That is a narrow purpose, and it is worth being clear about how narrow. NotanIzer is not a drawing app, a photo editor or a brush set. It reduces an image to a few tones so you can study its underlying structure, which is the sort of thing that matters when you are deciding how a painting or illustration should be organized before you commit to it.

The appeal for me is the speed of that check. Instead of squinting at a reference photo and guessing where the dark masses fall, you let the app flatten it and look at the result. It has been on Google Play since December 2017, with a 4.3 average from 80 ratings and more than 10,000 installs, and the developer's framing is simple: artists gain something when they view their work in another light.

The 50% split and its slider

The first tool divides an image at the 50% mark between bright and dark, producing a two-tone version of whatever you feed it. That is the classic notan study in its plainest form: everything above the midpoint becomes light, everything below becomes dark, and the picture turns into a pattern of shapes rather than a scene.

What makes this more than a filter is the slider. You can shift the dividing line away from the midpoint, which changes which parts of the image land on the light side and which fall into shadow. Nudge it one way and a face or a tree line may merge into the background; nudge it the other and details that were disappearing come back into view.

I like the way that turns a static conversion into something closer to a decision. You are not accepting one version of the image, you are testing where the boundary between light and dark serves the composition best. For a painter blocking in a canvas, that is a useful thing to be able to see before any paint goes down.

Grayscale for structure

The second function shows the image in a grayscale palette. Where the two-tone view strips an image down to a binary, grayscale keeps the full range of tones but removes color, so the eye stops being pulled around by hue and settles on form.

The developer's reasoning is that this lets an artist concentrate on the structure and design of the image. That matches how I would expect to use it: as a check on whether the underlying shapes hold up, before color is allowed to flatter them. A busy photograph can look convincing in color and fall apart once the color is gone.

Between this and the split view, you get two different questions answered. Grayscale asks whether the values are arranged well; the 50% split asks whether the main masses read clearly at a glance. Both are worth having when a piece is still at the planning stage.

Three, four and up to ten levels

The remaining tools take the same idea and add steps. There is a three-level version that sorts the image into three adjustable brightness bands, and a four-level version built the same way, each giving you a little more separation between the darkest and lightest areas without going all the way back to a full photograph.

The newer Levels tool goes further, breaking an image into even steps anywhere from three to ten. That range is the part that interests me most, because it lets you choose how much information you want to keep. Three or four levels give you bold, poster-like shapes; pushing toward ten gives a more gradual breakdown for images with subtler transitions.

All of these are adjustable, which is the thread running through the whole app. You are not stuck with one interpretation of your reference. You can move the threshold, change the number of bands and compare the results, then share an image in a number of ways once you have something worth keeping.

What it needs from your device

Getting started is a matter of having an image to work with and enough room on the device to process it. Adjustments can be memory intensive, so the developer recommends 20MB of free memory. That is a modest request by current standards, but it is a real one, and a phone or tablet already close to full may struggle.

There is nothing else to set up. The app costs $1.99 once, carries no advertising and offers no in-app purchases, so the whole tool is available from the moment you pay for it.

The app was last updated in February 2026. For a small utility with a fixed job, that kind of upkeep is what you want to see.

Who gets the most from it

This is a tool for people who make images rather than people who only look at them. Painters planning a composition, illustrators working out how a scene should be lit, and designers testing whether a layout holds together in tone are the readers I would point to it first.

It also suits anyone studying notan as a concept. Seeing the Yin Yang logic applied to your own photographs makes the principle concrete in a way that reading about it does not, and the range of level counts gives you plenty of variations to compare.

The cost is low and the scope is deliberately small, so the question is not whether it does enough but whether this particular job is one you do. If you regularly reduce references to light and dark shapes, the $1.99 is easy to justify. The app suits artists who want to study a photo's light and dark structure rather than touch up snapshots.

A focused buy for composition work

NotanIzer does one thing and does it in several ways: a movable 50% split, a grayscale view, three- and four-level breakdowns, and a Levels tool that steps from three to ten.

I would recommend it to artists and designers who want a quick, honest read on the light and dark structure of an image before they start work.

If that describes the way you plan a piece, this is a straightforward purchase at $1.99. If you need an app that draws, paints or edits photographs, keep looking, because this one is built for a single, specific stage of the process.