top quality modes
for both Draft and Final?
You might want
to rethink that if you ever get to the stage of working with
a large brush on 6 megapixel images :) It
is natural to select High Draft Quality but the meaning of draft
quality is rather special for warping and not really equivalent
to the sort of quality you think about in connection with interpolation
of images. You will find that there is almost no perceptible
difference if you work in the Medium Draft Quality Mode, while
the warp becomes faster and uses less memory. I think, in fact,
we set is as the default for this reason.
maps we distribute will be created in this mode to keep their
size manageable. Additionally, Photoshop deformation maps don't
come in any other flavor but Medium.
For the best
compromise between quality on the one hand, and speed and responsiveness
on the other: "I'd suggest the Medium mode."
you will only see differences between High and Medium Draft Quality
with long warps of a very regular pattern like a grid. On most
images even Low mode won't make much difference. (Our Low mode
is superior to the standard warping in many other packages, in
fact.) Additionally, you might want to be aware of another feature.
Suppose you start in High mode and switch to Medium during the
warp. Those strokes originally made in High Quality will retain
their quality even if future strokes are made at Medium Quality.
In other words, you never degrade anything you did previously.
Yet another thing to know about is that the maximum Hardness
of the brush is diminished slightly as you decrease the Draft
Quality. Since a brush of maximum Hardness is very rarely used,
this isn't going to be much of an issue. You are absolutely right
to specify the best Final Apply Quality. This makes far more
difference to the visual quality of the final image than anything
else in warping because this is where the nonuniform displacement
of pixels is taken into account. We only added the "Same
As Draft" choice for those people too impatient to wait
for the Final Apply. I definitely recommend being patient. -Kris
draft mode of the warp brush effect change the apply?
Let's try and summarize
some of the ideas behind the Draft Mode in warping: One way to
think of the Draft Mode is as a kind of resolution setting for
the deformation. In High Draft Mode, very fine changes in pixel
position can be represented. In Coarse Draft Mode, we can't define
the deformation as accurately. The Medium and Low modes lie in
between these two extremes. The less precise the Draft Mode,
the faster is the brush. Normally, there is very little difference
in appearance between High and Medium Draft Modes, so I would
recommend using Medium as the default. It is the best compromise
between precision and speed. Why then do we have Low and Coarse
For small images, we need precise
pixel positions because the image has very few pixels and each
of them has to be moved accurately to get a smooth warp. However,
for a 4 or 6 megapixel image this level of precision is a waste
of effort. If we want to make a warp of some size relative to
the size of the image we move few pixels in a small image but
an enormous number in a large image. For example, in a 200 x
200 pixel image a 100 pixel diameter brush will cover roughly
one quarter of the image. To cover one quarter of the image in
a 2000 x 2000 pixel image we need a brush that is 1000 pixels
in diameter. This huge brush would have to define the displacement
of 100 times as many pixels as the brush in the small image and
would be 100 times slower as a result. Ouch! So, for very large
images we can use a Low or Coarse Draft Mode. We aren't as precise
but we don't need to be because we have many pixels to play with,
not just a few, and we get a much faster brush. In fact, this
is the only way to get a brush that is fast enough to be usable
on images of several megapixels.
This image is an example
of how the Draft Mode affects the Twirl Brush.
if you are dealing
with a large image or the brush becomes painfully slow,
Exactly the same effects occur
in Push, Expand, Contract and Left or Right Twirls. Noise is
special and I'll deal with it later. The example image comprises
pairs of strokes, hard on the left, soft on the right, at the
labeled Draft Modes done with a 100 pixel diameter brush. As
the Draft Mode decreases from High, to Medium, to Low, to Coarse
the warp result begins to look a little ragged and wavy, especially
in regions with a large deformation. For the size of image shown
in the top portion of Twirl.gif you wouldn't want to use the
Coarse mode and might not want to user the Low mode either. The
bottom portion of the image shows what happens when you use the
Low and Coarse mode on an image twice as big as the former, with
a brush size that is also twice as big (200 pixels). After the
warp the result image was resized to half the original size for
comparison with the former image. You will see that the raggedness
or waviness is not nearly as objectionable. At the large size
the Low Draft Mode looks a lot like the Medium Draft Mode for
the smaller image. For the large size the Coarse Draft Mode is
very much like the Low Draft Mode used in the smaller image.
So, the general conclusion is that you should use Medium Draft
Mode as a default and,
set a lower Draft Mode.
let's take a look at the Noise brush using a 200 pixel diameter
at maximum Hardness and a maximum value for the Noise control.
that explains the difference I was seeing earlier in the warp
vs noise amount.
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The appearance obtained with
the various Draft Modes is labeled and it varies very widely.
This is the result of the special way noise is created. The brush
tries to pack higher and higher spatial frequencies into the
deformation up to the maximum possible. When you have a High
Draft Mode setting, the pixel positions are described in fine
detail and high spatial frequencies can be attained. The result
is the "jittery" look at top left. With a Coarse Draft
Mode the pixel positions are defined approximately and only low
spatial frequencies are possible. Consequently, the result at
bottom right shows only smooth, slowly varying deformations.
But what is that thing with
the question mark you say? It is actually the Noise brush in
High Draft Mode (same as top left) except that the size of the
brush is 100 pixels and not 200 pixels. A small brush can be
subdivided fewer times than a large brush and so cannot support
spatial frequencies as high as a large brush. The end result
is that the Noise brush is very dependent on settings.
How "jittery" it
is depends on the size of the brush as well as on the Draft Mode
you use. To make the brush more "jittery" increase
it's size and/or set a higher Draft Mode and set the Noise control
to maximum. To make the brush less "jittery", do the
opposite. Setting the brush Strength control to less than the
maximum will reduce the "jittery" effect but not quite
the way it changes with decreasing Draft Mode quality. The effect
is hard to describe verbally and is simply best seen in an image.
All the Noise brush samples were done with the maximum setting
of the Noise control because this is where differences are most
apparent. At a minimum setting of the Noise control, all the
strokes will be much more similar and the "jittery"
effect will be absent. It's worth doing a little playing around
with the Noise brush on a simple image like a grid to get a sense
of the range of behaviors it can give you.
I admit we could have made
the Noise brush much simpler at the expense of severely restricting
the range of effects. You can do this in practice by always working
at the minimum Noise setting. You will always get something like
you see in the bottom left image (especially if you avoid the
High Draft Mode). This could be useful for taking some simple
vector shapes, rasterizing them and giving them an "organic"
look (e.g. to make a Halloween pumpkin). However, you would never
be able to achieve the impressionistic effect at top right. That
needs a high Noise setting. We'd rather err on the side of more
power than less power, but it does make life a little more complicated
and high Noise settings make the brush very sensitive to all
the other controls. -Kris
was playing with warp some more, trying to find the cause of
another problem, and on the same checkerboard background, used
both the medium quality, and then the high quality draft mode.
At the end of this, I clicked on the checkmark to apply it, with
the apply mode being finest. The results of the 2 different modes
is quite different.
Expected from the above.