Image Size

[Hanna]

Why is it I can look at an image in Microsoft Photo Editor and it is 7" x 5", and I import it into Corel and it is 2" x 3", and I import it into CW, onto a board that is 6" x 8", and it is 1" x 3/4"? These are not exact figures but you get my drift. How do I figure out what the heck I am putting on the board?

[BoardSilly]

The designer brings it in as a small enough size so that you can position it and stretch to fit the area you want. If it brought it in at full size, and it was larger then the view area, you could lose it and not be able to get to the edge.

[Hanna]

Ok, I'm blushing. DUH Thanks;/ Man do I feel like an idiot

[shaddy]

I'm not positive (because I'm not sure how CW looks at things), but in general, programs are more interested in the actual Pixel count, as opposed to Size.

So if for instance, you had a 2"x2" image with a resolution of 100DPI, you would have an image with a pixel size of 200x200. Now import that into CW.

Now take that original image and decrease the size to 1"x1", and also increase the res to 200DPI. You still have a pixel size of 200x200. Import into CW and it will be exactly the same as the first time.

So, don't pay as much attention to the print size for the picture, that's just a flag within the image file. The important number is the total pixels.

Shaddy

[auriclux]

I found this old thread on image size.

Is there an optimum image resolution for importation into designer?

Thanks.
Scot

[jlitz]

I found this old thread on image size.

Is there an optimum image resolution for importation into designer?

Thanks.
Scot

128 DPI when importing an image into Designer.

[ChrisAlb]

128 DPI when importing an image into Designer.

I pretty much always use 200 dpi. But it really doesn't matter so long as you don't go below the 128.

What's more important to keep in mind is this. A large pattern dragged smaller will loose detail. i.e.. lines and spaces between them get smaller and harder for the bit to carve nicely. Now a small pattern dragged larger will keep the detail in tact. i.e. lines and spaces get bigger so the bit can carve them better.

I'm sure this sounds obvious but remember, we're working with a fixed size bit. If you get smaller than 1/16 with lines or spaces, the bit can't physically cut it. It might look fine on screen but it won't on wood.

Just my 2 cents.

[auriclux]

I pretty much always use 200 dpi. But it really doesn't matter so long as you don't go below the 128.

Thanks ChrisAlb and Jlitz.

I'm still just working with the s/w (because I can until the machine gets here).

Does it not matter because designer converts to 128 dpi? Does it do this from say 200 'down' and 50 'up'?

Also, I gather that greyscale converts to cutting depth. How does it do that? Does it, for instance, take the cutting depth (e.g. .255") and divide by a number (e.g. 255) for an increment of .001"?

Is there a place that I should be looking that has all the answers to these kinds of questions?

Thanks again for the help.
Scot

[ChrisAlb]

Thanks ChrisAlb and Jlitz.

I'm still just working with the s/w (because I can until the machine gets here).
Does it not matter because designer converts to 128 dpi? Does it do this from say 200 'down' and 50 'up'?
Also, I gather that greyscale converts to cutting depth. How does it do that? Does it, for instance, take the cutting depth (e.g. .255") and divide by a number (e.g. 255) for an increment of .001"?
Is there a place that I should be looking that has all the answers to these kinds of questions?
Thanks again for the help.
Scot

Hey Scott,

This is an excellent question. On my last big important project that required multiple levels of depth I went kinda crazy trying to figure this out. Because I was drawing the pattern from scratch in gray scale and having to layer the colors to achieve the proper levels, I found this to be a good "general rule of thumb".

Board thickness divided by 255 = depth change per shade. I'm not saying this "IS" the way the software & CW figure it but it worked very well for me. Assuming that 255 is the top of the board and 0 the bottom.

I was using 3/4" poplar for this job. So...

.75"/255=.002941" per shade. Obviously too small a number to work with so...

10 shades x .002941" = .029412" or 1/32" That's more like it.
So for this 3/4" thick project, I figured every 20 shades = 1/16" of depth change.

It worked out SO close that it's been my formula since. Seems to hold true so far.

As far as what the CW does with DPI, I don't know. I just work in 200 DPI for the "artwork" phase because it gives a nice balance (for me) for "smoothing" between shades. The higher the DPI, the smoother you can transition between shades. The lower, the more
"jagged" it is. I really wish pixels were ROUND...LOL

Hope that helps.

Chris

[auriclux]

... drawing the pattern from scratch in gay scale ...

Advance apologies, but Jay Leno and I are still in High School mentally, **snicker** he said gay ...

So for this 3/4" thick project, I figured every 20 shades = 1/16" of depth change.

It worked out SO close that it's been my formula since. Seems to hold true so far.

Brilliant!

Board thickness divided by 255 = depth change per shade.

Do you think that board thickness would influence this calculation? Perhaps a z-axis limit of 1" with 255 steps all works out to that 20 shades per .0625".

Hmmm, since I would guess that the z-drive is a stepper-motor, does anyone know the step size on the Z-axis?

Thank you again,
Scot