Random Effects: Watercolour from a render, one effect at a time

Upload one picture, try effects on it one after another, take back the ones that miss, and download the one that works.

An Overstory forest for Freiburg im Breisgau, 2024, after one pass of Wet-on-wet at Bleed 2. The free 1,748 × 1,223 px PNG, signature bottom right.

The forest above started as a machine-learning model. Overstory trained it on a year of satellite images around Freiburg and drew every decision tree inside it as a tree; the paler trees at the back are the ones that scored worst. Its export comes out flat and exact: pink paper, teal branches, square red buds. What does it look like wet?

Below is how that export became the watercolour above in Random Effects: one try that went wrong, three amounts of bleed, and a vignette that came off again. There is no settings link for this one, because the piece starts from an upload; the settings are in the captions, and the app is at effects.krshi27.art.

One picture in the middle

Open the app and drop an image on Upload image in the controls. It becomes the Working image, and every effect you apply replaces it, so effects stack on top of each other. The source here is a render; any PNG or JPG works, up to A4 at 300 dpi.

The upload, the three buttons that take things back, and the working image they act on.

Next to the working image sits the Effects gallery: four tabs of thumbnails, and a name appears when you hover over one. Click a thumbnail and a dialog opens with that effect's sliders and an Apply button. There is no live preview while you drag; the working image changes when you press Apply.

All twenty entries at their defaults on this export, computed with the app's own effect code. The Blend row shows the krshi27 logo because no blend image was uploaded.

I named the five Watercolour entries after the painting technique each one imitates, so that they don't all open with the same word and blur together in the gallery.

How this one got made

Glazing turned the wood into a cloud

Open the Watercolour tab, click Glazing and press Apply Glazing without touching a slider. The trees vanish. Glazing draws its glazes from the outline of each colour region and shifts every one of its eighteen layers a little from the last. That suits broad washes. The teal of this forest is one huge, tangled outline, and stacked and shifted eighteen times it became a cloud.

The same export before and after Glazing at its defaults. The teal of the branches spread into one cloud, the dark hill into grey smoke, and the red buds are gone.

Press Revert last and the export is back.

Wet-on-wet kept the trees, and Bleed decided how wet

Wet-on-wet separates the picture into washes, lets each one bleed into damp paper and darkens the rim where it thins. At its defaults it keeps every tree. The one slider that changed the piece was Bleed, how far pigment creeps past a wash's edge.

The settings of the final piece: everything at its default except Bleed, lowered from 4 to 2.

Apply it at the default 4 and the twigs go soft. Revert, try 8, and whole branches run into the paper. Revert once more and try 2: the branches stay crisp, and every red bud gets its own darker rim, which is where the picture starts to read as paint. Revert between tries, because applying Wet-on-wet on top of Wet-on-wet wets the picture twice.

One crop at Bleed 2, 4 and 8, every other setting at its default. Look at the thin twigs, which survive only on the left.

A watercolour pass takes a few seconds. I let only one effect render at a time across the whole app, because two heavy watercolour passes at once would run the server out of memory. If someone else is painting, the dialog tells you, and you press Apply again when they're done.

A vignette greyed the paper, so it came off

Effects stack, so you can keep going. On the Stylistic tab, Vignette at its default darkens the corners; on this piece it turned the pale paper grey. Revert last took it off again. Reset to original goes all the way back to the upload, and Clear image empties the canvas for the next one.

Two effects deep, one back, back to the start. Revert last steps back one effect at a time, up to ten.

From screen to object

Under Downloads, tick the terms once and PNG gives you the working image, capped at A5 and signed in the corner. The file also carries the list of effects that made it, written into its metadata. Order a print of this creation sits underneath if you want it on paper.

Other controls, one line each

• Blend image (optional), under the upload, is what the Blend entries composite against; leave it empty and they use the krshi27 logo.

• The Tonal tab changes brightness only, and leaves hue and saturation alone.

• Fluid sim is the real fluid simulation, where water carries the pigment. It is the only one of the five that simulates the water; the other four imitate the look directly.

Your turn

Open Random Effects, upload the last thing you exported from any of the apps, and try Wet-on-wet at Bleed 2. Then change one slider. If you like what comes out, send me what you made; I'll ask before I show it anywhere. Next, Random Effects as the finishing layer runs one short pass over three different apps' exports.