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Why a shadow must not take its element's blend mode
Put a logo on Screen and give it a drop shadow, and the shadow should still be a shadow. On this stage it is, because of the order things are drawn in. Here is the order, and why it matters.
Open the placing toolBoth files stay on your device — we only draw one on top of the other.
The order
An element is built in its own buffer before it meets the photograph: first the outline, then the element itself, then the shadow cast by both. Only that finished shape is mixed into the photo with the chosen mode and strength. The preview and the saved file use the same function in the same order, which is why the two match.
What goes wrong the other way
If the shadow took the element's mode, a logo on Screen would get a screened shadow — and Screen can only lighten, so a dark shadow screened onto a photo does nothing at all. On Multiply the opposite happens: the shadow multiplies with everything under it and turns into a bruise. Either way the shadow stops doing its job, which is separating the mark from the picture behind it.
When you do want a mixed shadow
Sometimes a soft, coloured glow that mixes with the photo is the look you want. Make it a second layer — duplicate the element, darken it with the ink colour, blur it with a mask feather and give that copy its own mode. Each layer keeps its own mode, so the result is under your control rather than a side effect.
In short
- Built first
- Outline, element, then its shadow, in the element's own buffer.
- Then mixed
- The finished shape, with the chosen mode and strength.
- Shadow
- Offset, blur, strength and colour; turns with the element.
- The shadow is part of the element, so the element's opacity fades the shadow with it.
Questions
- Why does my shadow disappear on Screen in other apps?
- Because there the shadow takes the element's mode, and Screen cannot darken. Here the shadow is drawn before the mode is applied.
- Does the shadow turn with the element?
- Yes. Its offset is measured in the element's own frame, so it rotates with it.
Where to use it
- Add a logo to a photoOpens small, in the corner, inside the margin a crop is least likely to take.
- Place a PNG on a photoA transparent element starts centred at a restrained share of the frame, ready to size and position.
- What the blend modes doMultiply, screen, overlay and soft light, with the arithmetic said in words.
- Place something on a photoThe stage and a deck of layers: logos, stickers, textures or a second photo, each moved until it looks right.