Novice ask for stippling method

[Guy Lemaire]

Hello. I am quite a novice. I would like to know if there is a way with S.A. to transform an image into a point, (stippling) if possible, it would be the best of the best for me a (vector stippling). I hope to be understandable because my English is poor ... I am French-speaking Belgian! Thank you

[Synthetik]

Yes, you can do all kinds of different half-toning effects, including raster or vector stipples. I'll try to put togethere a tutorial post on some approaches and post it here later today.

[Guy Lemaire]

Thanks, it's roughly this but in my case the little circles should never overlap!

I am very new to this and I have a bit of a problem finding a method for this!

My points are only monochrome and never touch!

I hope to get there with S.A. but I'm a little lost :-)

[Synthetik]

Do you just want solid flat tone fields of dispersed round dots like above?

Of do you want something that is essentially halftoned with the dispersed pattern of dots?

And do you want partial doting (clipped to image features), size modulated full dots, or just dots of one size?

[Guy Lemaire]

Hello, thank you, I would like dots of only one size and the halftones would be the result of the density of dots ...

[Synthetik]

OK, fixed size dots, tone density halftone with the dispersed pattern, no partial dotting, not size modulation for dotting.

One thing i want to point out is that the source image used for the example you posted is highly optimized via contrast manipulation for this kind of rendering. So don't be afraid to manipulate the contrast and lightness of your source image to drive the painted results where you want them to go.  So boost the contrast, and lighten it up enough to compensate for the dot overlap in the dark areas (which is going to lead to a darkening in the rendered tone curve output).

You have a lot of control in the paint synthesizer over where paint strokes are drawn, when paint strokes stop, what the stroke and the nib looks like, etc.

So you want single isolated round paint nibs.  That means you want the Max Path length in the Path Shape control panel to be set to 1.

You need to set the size of the dots in the Brush Source control panel.  

You said you wanted to use vector paint, so you have to set that up accordingly in the Vector Output control panel.

I'll run through how to start from scratch and dial in some different options to play with for what you are specifically asking for.

I tend to personally like partial dotting, as well as brush size modulation, so i'll show how to add that if anyone is interested.

I also wanted to point out this tip on controlling where automatic painting happens in the canvas. 

You should read this before reading through my run through on how to build it from scratch, because then what i'm going to edit in the paint synthesizer will be clearer.

I'll do the 'build it from scratch' tutorial in another post in this thread.

[Synthetik]

Is this the kind of effect you are looking for?

I used the paint synthesizer to put this together.  I'm painting single nib vector paint blobs.  I've turned on something to generate partial doting for the individual stipples.  I turned on time particles so the stipples had continuity across the paint animation.

You can output this as svg if you want, since it is all vector.

[Synthetik]

 Ok, let's run through how to build a dispersed dot stipple style halftone from scratch in the paint synthesizer.  What we are going to build generates something like this.

You can see that i'm using the Spheres on Path option for the Vector Stroke Type in the Vector Output control panel.

 

But to get started, it is always a good idea to start from a known configuration of the paint synthesizer.  If you press the Init button down at the bottom right of the paint synthesizer Editor, the current control panel with be initialized. To initialize all of the control panels, hold down the shift key and press Init.

Then, goto the Vector Output control panel and switch the Vector Stroke Type to Sphere on Path.  

Then, goto the Brush Source control panel and setup your dot size (the size of the vector sphere being drawn for the brush nib).

I made mine 16x16, probably because i was thinking about working with variable dot sizes later on.  You can make it 1x1 if you just want single pixel dots.

Next, goto the Path Shape control panel, and dial in the Max Path Length to be 1.

You want to do this so that only a single paint nib draws for each path generated by the paint synthesizer.

Next, goto the Paint Color Source control panel.

Set the Color Mode to Black.  We are doing this to force painting with black dots.

Note that init defaults the Randomize to 10. You want to set that to 0 if you do not want some small color randomization going on with the individual dots.

Now goto the path Start control panel.

The default Generator option shown above actually generates a fairly dispersed sampling pattern.  Smooth Random 1,2 and 3 all do, so it is worth experimenting with them in comparison to the Clumpy Random one to see the difference.  You could setup a fixed Max Stroke setting and see what the different sampling patterns generate.

The actual sampling patterns are being generated at the pixel level. So as you start to increase the dot size, there will be some overlap in the dispersed patterns, because they are computed at the pixel level.  Smooth Random 1 is a kind of Poisson noise sampling, so close to an ideal dispersed pattern, but not totally there because it is probabilistic in nature.

You can also play with different Probability options. For example, if i turn on the Inv Lum Gain Prob Weight option for Probability, and then set the Prob Gain to 70, i get the following patterning.

You can see that the probability option i selected is weighting the sampling so it occurs more frequently in darker areas of the source image.

If you run this multiple times, the density will build up more, and you get the following.

The decisions about whether to keep a path start point coming out of the Generator or not is based on some probability.  One way to think about it is that a weighted coin is flipped, and then we use the path start point (or not) based on the result of the coin flip.

So this is one approach to take.  Because we only make the decision to paint the dot or not based on a coin flip (probability), it is not going to be as smoothly designed in nature as what you are looking for.

So i used a slightly different approach. I didn't use any of the Probability weighting options in the example at the top of this post. I used the init setup for the Path Start control panel.

I then went to the Path End control panel, and set it up as follows.

I turned on 2 specific things.

First, i'm making the assumption that i am starting by erasing the canvas to white.  And then drawing black on top of that. So i set the Visual Error parameter to WhiteCanvas Lum Err.

What this does is check if my path drawing is going to reduce the visual error (or increase it).  If it is increasing it, then the path drawing is stopped early.

Since we are only drawing a path length of 1, this is only going to effect whether the single paint nib is drawn or not.

Now the dots i am drawing with are larger than a singel pixel.  And we want to take that into account. So i setup the End Calc parameter to run the path end calculations along the maximum brush radius (as opposed to just at the center of the path point).

And that is all of the hand editing i did the the default init preset to get the following.

Note that i had to hit the Action button multiple times to get it to fill in fully.

 

Again, i'm going to point out that you really want to optimize the contrast and lightness of the source image you are working with for this kind of halftone effect.  Otherwise, it is going to be too dark due to the dot overlap.  I used the Bias/Gain Adjust option in the Adjust operation mode to do that.

Erase the canvas to the Source.

Mouse down in the canvas and move the mouse accordingly in 2D to interactively get the tone curve you want. Release the mouse.

Run the menu command below to move the canvas image into the Source.

So do this initially to prep your source image for the effect prior to running the effect.

You could record these steps in a PASeq if you wanted to, along with the erase to white and the action steps needed to make the halftone effect.

[Synthetik]

An interesting twist to this kind of dispersed dot halftone rendition is to add some brush size modulation based on the source image luminance.

I set that single editing change up below, starting with where we were in the last post.

I think not taking the Min Size Range all the way to the bottom can be artistically more effective for this kind of effect.

 

[Synthetik]

Partial dotting can also be very effective for this kind of dispersed dot halftone rendition.

I took our original non size modulated settings, and changed what i was doing in the Vector Output control panel slightly.

Note that i changed the Vector Stroke Type from Spheres on Path to Circular Region.

I did this because i knew that i would then have access to the Clip Blob feature that is available in all of the region path structured Vector Stroke Types.

I set the Clip Blob to Color Clip.  With a Color Error of 40.

So what Clip Blob is doing when it is turned on is that it tries to add some clipping to the vector shape of the 'blob' (a circular region in this case) based on the color difference between where the circular region outline path is being drawn and the center of the circular region.  It is the vector paint equivalent of the Nib Masking available in the Paint Fill Apply control panel for raster paints.

And you can see that when the Clipping of the vector region is turned on, you get a much tighter rendition of the source image.

 

Again, everything we are doing here is vector painting, so you could output it as a svg file for resolution independent rendering to the final canvas size of your choice.  You can do that size-up re-render of the svg file in Studio Artist (File : Import: Import SVG as New Canvas menu command), or in some other program that opens svg files.

[Synthetik]

Of course you aren't limited to just vector dots when taking the particular approach to configuring the paint synthesizer that we used for this dispersed dot halftone project.

You can easily extend it out to build all kinds of different custom vector litho paint presets.  And you can work with them in different ways in a Paint Action Sequence to build up more elaborate effects.

One quick example i threw together based off of the partial dot presets we built earlier in this thread is shown below.

So i was trying to put together something like a linoleum block or wood cut print effect.  All in vector so it is resolution independent.

I setup the Path Shape control panel so that randomized path lengths were drawn as seen below.

I wanted the paths to be drawn as vector region shapes (as opposed to being pounded our by repeated application of circular vector dot regions along the path).

So, i went to the Vector Output control panel and changed the Vector Stroke Type from the Circular Region to the Bezier Region option.  Bezier region refers the bezier region defined by the current paint path being auto-generated by the paint synthesizer.

Note that the Bezier Region vector stroke type also has access to the Clip Blob features we used before.

And in the first screen shot you can see that we are using the Source Hue to generate the output of the Path Angle control panel for the automated path drawing.

 

The visual effect shown in the top screen shot was generated using the Paint Action Sequence (PASeq) shown below.

I started by erasing the canvas to white.

I then deleted anything inside of the bezier path frame.

I then auto-generated bezier paths from the source edges.

I size pruned and close connected those auto-generated bezier paths sitting in the bezier path frame for the layer.

I then painted in the bezier path frame using our custom edited vector paint preset. So i'm drawing in the edge structure using the vector paint preset.

I then run multiple applications of the same paint preset as an AutoPaint action step.

I have to run it multiple times because of the 40000 Max Stroke restriction.  You can't go higher then that right now, and you have to do it to get the canvas coverage needed to pull the final image together. 

So you just keep running it multiple times until you get the coverage you want in the canvas.

Just make sure you leave Reset Generator set to Off in Path Start control panel, because if you tie it to a single random seed by turning it On, then the repeated applications of the auto-paint would never completely fill in the canvas because they would always be drawing to the same canvas coordinates in the same sequence.  There are many reasons why one might want random behavior for a paint preset, and this is a good example of one of them.

 

Even through we are painting with vector regions representing hand drawn cuts in a block, the vector paint is still smart about restricting paint coverage based on that Visual  Error parameter setting we setup for the initial dispersed dot paint preset we have been working off of.  So it will stop drawing a paint path if the visual error in the canvas would get worse if it did it.  You can see how the auto-drawn paint strokes are smart about cutting out when then get near the first to be painted black source edges.