Some time ago I wrote/screen-captured a tutorial on Painter blending basics and posted in CA & CG society forums. A few years ago, actually. Since I am still getting a nice feedback (and/or requests for sharing/re-publishing), I decided to re-publish it here too.
The tutorial is intended just to show some possible way (one of many, actually) of how to use Painter Blenders (incl. a few very basic general rules for beginners). It is definitelly not "the only way" of how the blending technique works, since - I am sure - different artists use their own different approaches.
My English is not perfect,
so the text might be a bit difficult to read - I am sorry if so.
Hopefully everything makes sense ..
(and hopefully all the *gif animations are playing ok),
a.
The tutorial is intended just to show some possible way (one of many, actually) of how to use Painter Blenders (incl. a few very basic general rules for beginners). It is definitelly not "the only way" of how the blending technique works, since - I am sure - different artists use their own different approaches.
My English is not perfect,
so the text might be a bit difficult to read - I am sorry if so.
Hopefully everything makes sense ..
(and hopefully all the *gif animations are playing ok),
a.
Painter blending basics /tutorial (Painter X)
for controlled blending
by Alena Hovorkova
The Blenders (unlike in Photoshop) are a separate category in Painter. There is a bunch of pre-defined blenders in there, but - in fact - you needn´t use only those pre-defined blenders; you can even make your own custom blenders, very easily, from (many, not all) standard painting brushes you use for painting ...
for controlled blending
by Alena Hovorkova
The Blenders (unlike in Photoshop) are a separate category in Painter. There is a bunch of pre-defined blenders in there, but - in fact - you needn´t use only those pre-defined blenders; you can even make your own custom blenders, very easily, from (many, not all) standard painting brushes you use for painting ...

A simple "trick" how to turn a regular painting brush into a Blender:
The "trick" here is the "Resat" slider (= Resaturation value; available either at the upper Property Bar - or - within the Well pallete).
Not all the painting brushes - but a lot of them - HAVE this control/slider available. If you set the "Resat" value to 0 %, this will cause that the brush won´t "add color pixels" any more, but instead - it starts behaving as a "dry" brush (adding NO new information), that only affects/alters (in a certain way, depending on the brush type and other settings) the colors/pixels already painted ...
This "Resat" value modification is especially usefull when you want to keep the same characteristics of the painting brush also while blending (size, opacity, bristels/tip type, grainy structure if any applied etc .. ).
Often it is a good idea to increase also the Bleed value/slider, so as the colors/pixels can mix/blend together more naturally ..
In the following *gif animation you can see the Hard Pastel - used for painting first, and then - the same brush after changing the Resat and Bleed values - used as a blender for blending:
The "trick" here is the "Resat" slider (= Resaturation value; available either at the upper Property Bar - or - within the Well pallete).
Not all the painting brushes - but a lot of them - HAVE this control/slider available. If you set the "Resat" value to 0 %, this will cause that the brush won´t "add color pixels" any more, but instead - it starts behaving as a "dry" brush (adding NO new information), that only affects/alters (in a certain way, depending on the brush type and other settings) the colors/pixels already painted ...
This "Resat" value modification is especially usefull when you want to keep the same characteristics of the painting brush also while blending (size, opacity, bristels/tip type, grainy structure if any applied etc .. ).
Often it is a good idea to increase also the Bleed value/slider, so as the colors/pixels can mix/blend together more naturally ..
In the following *gif animation you can see the Hard Pastel - used for painting first, and then - the same brush after changing the Resat and Bleed values - used as a blender for blending:

A few basic "workspace rules" for good blending results:
Though it is not obligatory, it is a good idea to keep/follow a few simple rules:
Though it is not obligatory, it is a good idea to keep/follow a few simple rules:

(1) for best results - you should always blend only in a separate layer above the canvas (or above the layer with the painting, if any); the blenders can be used also in the canvas, but - to get best results - blending works best when in separate empty layer, above the painting/pixels you want to blend (this is a good way how to work also for another reason - while blending in a separate layer, you wont ruin your underneath painting in case your blending process wont turn out well); personally - I got used to keeping every single "important" element of an illustration in its separate layer - until I am satisfied - then I drop everything down, and - again - create another new empty layer/layers above, to proceed with something else .. and so on ..
(2) while blending, check "Pick Up Underlying Color" (but - this applies only to the blenders that have the Resaturation attribute/control available; both the Resat control and this attribute/control are related to the underneath color/pixel information, that may be included/picked up/merged into the above blended area, very naturaly);
(3) the Resat value setting - when available - as I already mentioned - is the way how to control/switch between painting/blending process
You can of course change other attributes too, the Opacity and the Size are usually the most often used/useful ones while painting/blending, etc.
What makes the difference while blending ...
Blending process in Painter may be a real whole alchemy - since there is so many various issues that may affect the process and the results;
not only the brush/blender settings are important to achieve certain blending results - also a few other things make a great difference - I mean - for example - the way how the brush is dragged: the speed, direction, first starting "sampling" position of the stroke, number of repetition of strokes in the same area etc. - and also - the "starting/initial" information available (colors/pixels already painted) to work with (to be blended) ...
So - this means - you can get many (many!) absolutelly different results from the same initial painting, whatever it may be (you can start with something really simple, a few painted brush strokes, for example, see below), since the blending process may be performed in many different ways, which leads to different behavior of the Blender.
Here´s an example of what I am talking about:
to make things simple, in the folowing image I only used ONE (the same for all examples) simple pre-defined "just add water" blender, and - in all 5 examples - I started up with the same initial simple black/white strokes (seen in the red-border).
The only difference here was the WAY HOW I dragged the brush (direction, repetition, "sampling" starting positions etc.)
(2) while blending, check "Pick Up Underlying Color" (but - this applies only to the blenders that have the Resaturation attribute/control available; both the Resat control and this attribute/control are related to the underneath color/pixel information, that may be included/picked up/merged into the above blended area, very naturaly);
(3) the Resat value setting - when available - as I already mentioned - is the way how to control/switch between painting/blending process
You can of course change other attributes too, the Opacity and the Size are usually the most often used/useful ones while painting/blending, etc.
What makes the difference while blending ...
Blending process in Painter may be a real whole alchemy - since there is so many various issues that may affect the process and the results;
not only the brush/blender settings are important to achieve certain blending results - also a few other things make a great difference - I mean - for example - the way how the brush is dragged: the speed, direction, first starting "sampling" position of the stroke, number of repetition of strokes in the same area etc. - and also - the "starting/initial" information available (colors/pixels already painted) to work with (to be blended) ...
So - this means - you can get many (many!) absolutelly different results from the same initial painting, whatever it may be (you can start with something really simple, a few painted brush strokes, for example, see below), since the blending process may be performed in many different ways, which leads to different behavior of the Blender.
Here´s an example of what I am talking about:
to make things simple, in the folowing image I only used ONE (the same for all examples) simple pre-defined "just add water" blender, and - in all 5 examples - I started up with the same initial simple black/white strokes (seen in the red-border).
The only difference here was the WAY HOW I dragged the brush (direction, repetition, "sampling" starting positions etc.)

The blending technique - controlled by the user this way - may be then very flexible (this was only a simple b&w example combined with only one simple blender) -
just imagine how versatile blending may actually be ...
- you can use not only black/white limited pallette ..
- you can use whatever blender/brush type you might need ..
- you can start up with whatever initial painted shape you may want (that you paint first, to be blended then)
- you can choose whichever way/direction/strenght/intensity of blending you want
- you can even combine blending and painting on the fly - after defining some basic blended shapes, just add/paint some more strokes of "color/pixel information" to work with again, and blend again ..
etc ..
The technique (basics)
While blending with blenders - the underlying colors/pixels are dragged & spreaded smoothly in the direction you drag - but - not only the direction (besides other things) is important for the final look of the blended stroke, but also the "starting" position of each stroke is important, since the blender/brush samples the information under the cursor each time you start a new stroke - and - only the "available/sampled" information is then spreaded to other areas. Which means (looks simple, and it is, actually) that for blending it makes a great difference WHERE you start dragging (see the little circles) and WHICH DIRECTION you drag the blender/brush (see the arrows);
just imagine how versatile blending may actually be ...
- you can use not only black/white limited pallette ..
- you can use whatever blender/brush type you might need ..
- you can start up with whatever initial painted shape you may want (that you paint first, to be blended then)
- you can choose whichever way/direction/strenght/intensity of blending you want
- you can even combine blending and painting on the fly - after defining some basic blended shapes, just add/paint some more strokes of "color/pixel information" to work with again, and blend again ..
etc ..
The technique (basics)
While blending with blenders - the underlying colors/pixels are dragged & spreaded smoothly in the direction you drag - but - not only the direction (besides other things) is important for the final look of the blended stroke, but also the "starting" position of each stroke is important, since the blender/brush samples the information under the cursor each time you start a new stroke - and - only the "available/sampled" information is then spreaded to other areas. Which means (looks simple, and it is, actually) that for blending it makes a great difference WHERE you start dragging (see the little circles) and WHICH DIRECTION you drag the blender/brush (see the arrows);

This is a very powerfull way how to control the blending process: you can spread/"move" the color/pixel information where you need, so - you can "model" the final shape of your choice in a pretty precise way (while using small brushes near the edges, watching out not to blend what you do not want to blend, etc.) ...

(note: the *gif here is only a low quality demo, real blending results are nicely smooth, actually)
As you may see in the demo - another important thing to keep in mind is WHICH areas to blend, and WHICH just not.
You can either shapelessly blend everything together - just to get uniform smooth transitions between colors/values, without any other particular "painting" purpose -
OR - you might want to keep some shapes or edges "untouched" while blending.
So - this is another little "tricky" (but pretty simple again) issue when blending: making decission on what areas to blend, in which direction. This kind of planning your work allows you to achieve different shapes/characteristics of the final blended areas. For example - when starting up from two single adjacent black/white strokes (see the following example) - you´ll get completely different results in case you decide to keep the middle line (and to blend the rest) - or - in case you decide to keep the outer edges of the two initial strokes (and blend the space in between) ...
And the way you spread the existing pixels/colors has a great impact on what the final "blended shape" looks like ..
This kind of controlled "one-sided" blending is actually the very basic/fundamental and the most powerful blending technique, that lets you achieve (combined with a little pre-planned initial painting) whatever shape you might think of, literarly ..
As you may see in the demo - another important thing to keep in mind is WHICH areas to blend, and WHICH just not.
You can either shapelessly blend everything together - just to get uniform smooth transitions between colors/values, without any other particular "painting" purpose -
OR - you might want to keep some shapes or edges "untouched" while blending.
So - this is another little "tricky" (but pretty simple again) issue when blending: making decission on what areas to blend, in which direction. This kind of planning your work allows you to achieve different shapes/characteristics of the final blended areas. For example - when starting up from two single adjacent black/white strokes (see the following example) - you´ll get completely different results in case you decide to keep the middle line (and to blend the rest) - or - in case you decide to keep the outer edges of the two initial strokes (and blend the space in between) ...
And the way you spread the existing pixels/colors has a great impact on what the final "blended shape" looks like ..
This kind of controlled "one-sided" blending is actually the very basic/fundamental and the most powerful blending technique, that lets you achieve (combined with a little pre-planned initial painting) whatever shape you might think of, literarly ..

(pls note: the arrows in this example do not show the direction of particular strokes, but - this time - only the "overall blending/spreading direction")

Here you can watch a few (very simple & short) demo movies
showing the process:
movie #01: defining precise shapes
movie #02: keeping the edges sharp
movie #03: "modelling volume" via blending


+ a little one :)

original CA post/link:
http://www.conceptart.org/forums/showthread.php?p=2475778#post2475778
http://www.conceptart.org/forums/showthread.php?p=2475778#post2475778