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Unfiltered images for comparison.

General filters

These filters may be available on for multiple layers or panels.


Filters ► Subject ► Rotate
Filters ► Palette ► Rotate
Filters ► Canvas ► Rotate

Rotate the subject 90 clockwise. Twice is upside-down. Three times is anti-backwards.

Subject specific filters

Smart blur

Filters ► Subject ► Smart blur

The effect is subtle and varies with the size and type of the subject but it can make a big difference to the complexity of the paint areas and their outlines.

Oil filter

Filters ► Subject ► Oil filter…

This filter produces an oil painting effect. It is useful in reducing texture detail and smoothing the outlines of paint areas.


Filters ► Subject ► Saturation…

We can supply a saturation value from 0 to 100. The default value is 1.0 for no change.


Filters ► Subject ► Brightness…

We can supply a brightness multiplier value from 0 to 3.0. The default value is 1.0 for no change.

Contrast enhancement

This filter stretches each of the red green and blue channels to use the full range available.

Filters ► Subject ► Contrast enhancement


Filters ► Subject ► Posterization…

Subject ► Warp

A sub-menu. Not released yet (but high-up on the list) (-enableassertions).

Filters ► Subject ► Warp ► Schaefer warp

Filters ► Subject ► Warp ► Perform subject warp

Filters ► Subject ► Warp ► Define incremental subject warp points

Filters ► Subject ► Warp ► Perform incremental subject warp

Filters ► Subject ► Warp ► Define bulge subject warp points

Filters ► Subject ► Warp ► Revert subject warp

These controls will allow us work from our own drawings rather than tracing the subject image and still be able to line up the canvas images so we can compare the colours to the subject. We will be able to do our own a free-hand drawing and then, as a one time task, warp the subject to match the it and create aligment markers so that subsequent canvas alignments will work.

Canvas specific filters


Filters ► Canvas ► Align ⇧⌥A

Canvas image alignment is explained here.

Other filters

Sketch filter

Filters ► Subject ► Sketch configuration…

This is technically a subject filter but the result is written to its own sKetch layer rather than the filtered Subject layer which is why it's in the Other filters sub-menu.

Selecting this item will cause the sketch configuration dialog to be displayed.

The contrast multiplier value controls how high contrast the sketch is, that is the lighter values are pushed even lighter and the darker values darker.

The contrast centre value controls where the centre of this contrast push is. The further a value is from the centre the more extreme the enhancement. If it's near the middle the the lightest and darkest values will be made extreme. If it's near the top the light values will remain largely unchanged but any darker values, which will be most of them, will be made even darker.

We should probably aim for much less detail than we think we'll need. The sketch is only there to give us a broad placement map of the larger objects in the scene.

Lighting correction

This filter can be used to alleviate lighting problems on the canvas or palette. It is always better to correct the lighting rather than use this filter. This is provided for very large paintings where that may not be possible. It is a simple linear correction and will not cure vignetting or other complex lighting problems.

The image must be currently loaded as the canvas, palette or subject. It should not have had any other filters already applied and should not have any associated palette entries to start with.

There needs to be two widely separated areas that should be the same colour, but aren't. Perhaps you can use the backing board on an easel which is larger than the canvas. It may be that we need to place sheets of card as targets before taking the photo. They should be on opposite sides of the photo in the direction of the lighting problem so they a appear to be different colours even though they're not.

Make selections in these areas to create palette entries. They should be the only two entries for this image.

Select them and then do:

A linear colour grading is applied to the image. The two selected areas are re-sampled and hopefully have become more similar colours. If they have become the same colour only one entry will be shown.

The palette entries are re-sampled at the end and should then be the same colour (ish). It is usual to delete these entries afterwards.

This filter doesn't have an undo so you should save the project before you apply it.