pic suitable ?

[Xxray]

Well, if I could get to the point where the depth is correct, I can work at line spacing at my leisure.
I see the picture in there, its close but no cigar. I have looked at many tutorials, I have received and followed much advice, I cannot seem to make a successful cut, for what reason I do not know.
Why the faces and the white dress, for instance, are the highest parts when they should be the deepest, I wish I knew. Use a black and white pic, inverted colors as everyone suggests, and still the whites are high and the darks are low. And max depth .21, still too much material left, am confident its not a machine accuracy issue, I routinely make precision cutouts.
I don't know, guess its coming down to trial & error until I get it right, or move on to something else.

[ssflyer]

It's your image. The faces are the darkest part of the image, which is why they are higher. And the dress is not even close to the whitest part of the image. Everything is going to be cut relative to the whitest part. Take a look at the sunlit edge of his collar, sleeve and pants - they are cut deep.

The picture also has no contrast - light to white clothes on a white beach, with seriously underexposed faces. You could try to mask the skin areas and selectively lighten, adjust exposure, etc., but in my opinion, you'll never get a really good litho from this shot.

[BDM]

Ron is probably right, but if you want to experiment some more, I would remove the background and then touch up those bright areas on the man to match his clothes and then try a cut or at least see what the preview looks like. If you haven't done so already, I would convert the picture to a bmp or tiff before working on it.

[Xxray]

You got a point Ron, something I have thought about, hence the title of this thread.
So if clicking "invert colors" makes the darker faces higher, would leaving it blank make them lower ?

[ssflyer]

Nope. Think of white as the lowest point in your carving. Anything in your picture that is not white will be cut higher than that. I played with the image for a bit, but since I don't have the original (hopefully higher resolution), I can't really get good results with it.

The biggest issue is that the faces are way underexposed. I can adjust exposure, brightness, contrast, etc., but only so far...

If you do have a high res version, try posting it, or putting it up on DropBox, One Drive, Google Docs, etc., and I'll see what I can do

[Xxray]

No, the original pic I posted is what I got to work with, probably a cell phone pic

[Xxray]

Good Morning, I have been successful in these, and thought I would share my 2 cents.

I usually aim for leaving .04 at the lightest point in the corian. This appears nicely with the ones I have done. Once I figured out the White is thin and Dark is thick I almost visualize the final product when I look at a pic. I use a light blue plastic for my preview and this gives a good representation. Future updates may allow for backlit preview.
As for the angle, it is a matter of preference, but 315 will start in the lower left hand corner and works well for me.
As for line spacing, I typically use the 8% as I find it gives great detail, might be a bit of overkill, but I find it makes it pop. I have also used low grade cell phone pics and had good luck straight from the camera. I did this more of a whim, but it worked extremely well. I think that it depends upon the subject matter and the amount of detail one can extract from the lower res. Mine was more or less a black and white photo, so it did not cramp the style at all.
I still use the 30 deg v-bit single pass strategy, as it is what works for me, but where I differ from most is I zero on the bottom. I have found some corian to not be uniform in thickness and this allows me to adjust. A word of caution, this ends up with extra air passes that can double and triple the time to carve. Not sure why, but did not get a great answer when I enquired either. All reference in the training is to the top.
As pointed out, make sure to invert the light/dark and don't be afraid of the contrast slider either.

I think I see what you mean, seems to do 3 to 4 passes per line ... Not exactly "air passes" as it does shave material on the way down, but kinda tough to see the purpose of them. Maybe dependent on tool type ? I don't know but yeah, sure increases cutting time.

[Xxray]

I think I finally nailed one with a pic of one of my old girlfriends !
Did one that I forgot to invert colors so the white points were high. Did another that just went through on some low points so that was ruined.
Adjusted depth a bit and got this, 8x8" took about 2 hours. Remains to be seen how I'll backlight it, not sure if white LED's will be sufficient ,,, But I'm happy to make some progress.
I think I'll try the original pic in this thread one more time without inverting colors, in theory this should make the faces more prominent ,,, And if I cut as deep as I can as I did with this one, just might work out.

Never thought I'd work with a material that I hate more than mdf, but corian just might be it. Messy, chalky, hard to clean up and sticks to everything like glue.