Interesting discoveries while scanning/retouching photos

I've discovered a few misc. things while working on retouching some old photos:

1) When scanning photos into PhP, I find that I have to go to file-new-import to get the scan started. If I go to file-import-select source, even though the dialog box comes up to select my scanner, nothing happens. Is this true for others?

2) Although you cannot clone from one layer to another you can clone from one open file to another. Has this already been well discussed? Probably so.

3) When I scan at high resolutions I get some white speckles on my image. The scanner bed is clean and the speckles are not on the photo. What might this be?

4) I discovered a cute trick for cloning on a new photo border, say if you've cropped part of the picture and want to add back a side or two of photo edge to make it look like you have the entire photo. If you set your clone tool close to the outside edge of the photo border, you will get a very sharp clean line, if you then clone this to be the inside border (the one touching the picture).


Sasha

Hi Sasha,

1) "File/Import/Select source" just sets up the right Twain driver for a subsequent "Acquire", as far as I know. In my case, the "Select" dialog includes my scanner and my digital camera, so I can select one or the other. So you're right - you either have to do File/New/Import or "File/Import/Acquire" to start the selected device. But you don't have to "Select" each time unless you're choosing a different device.

2) Yes, its a known bug in PhP8 - hopefully to be patched!

3) Dunno

4) Neat trick indeed! Or you could increase the canvas size and put your cropped image in the centre of it, then fill around with white.

Martin

Martin,

1) Oh, that was the problem! Thanks.

4) I'm not sure how you would do that 'around the edge' fill. Maybe it is very simple. The way I did it was surprisingly fast, and if you were looking for a very authentic look, it also replicates the minor flaws of a photo that has been around awhile.

Sasha

Sasha,

Yes, cloning would be the best way to get that authentic look, I agree.

As for that around the edge fill, just use the "paintpot" fill tool. Alternatively, I've just realised that its easier to set the background colour to white before increasing the canvas size. Then the extra space around the image is already white.

No clues yet on those scan imperfections? Are they black and white images? Edit: I did read that you can get speckles on scanned printed pages, as a result of the printing process. Photos should be OK, though. Some image editors (e.g. PhotoShop) have a Despeckle function. Not PhP, though (yet!).

Martin

Sasha,

White speckles sometimes seem to start showing up when images are sharpened. Is there a possibility that you have a sharpen filter set in your scanner controls which may be responsible?


Keith.

Keith,
My scanner controls has an automatic 'unsharp mask' checked. Could this do it? Other then that, I usually adjust the histogram some, and leave the other adjustments alone.

Martin, yea, I thought of the white background, too after I posted. :-)

Sasha

Sasha,

Duno about whether the unsharp mask would cause the effect, but I can't see why it would be there in the first place. Seems a bit self-defeating to me

John

Sasha

My Canon scanner has an unsharp mask, too, but I generally leave it switched off. Its in the "advanced" controls, anyway. I'd guess that Keith may be right, though - sharpening a scan could lead the software to add speckles. I still think it may be something to do with the type of image you're scanning (photo, printed page, crinkly old photo ...).

And I never did understand why an "unsharp" mask is one that sharpens an image, until just now, when I found these words:

The Unsharp Mask filter works by creating a blurred (or Unsharp) copy of your image, and subtracting the Unsharp image brightness values from the original image brightness values. Changes in contrast (dark to light) in an image are what make an edge really an edge. In a blurred image, those contrast changes are more gradual; there are more mid-tone pixels used in areas of changing contrast. (Soft, blurry edges are created digitally by increasing the width of an edge, inserting a more gradual change from dark to light. More midtone brightness values along those edges = reduced contrast.)

Subtracting this low-contrast, blurry image from the original image has the effect of increasing the contast of those original pixels.

Hmm.


Martin

I am going to take the unsharp mask off. I think that may be causing the problems.

Here is more information on the unsharp mask] http://www.scantips.com/simple6.html[/url].
This site has been my main tutorial for scanning. Very good site.

The images I have gotten this speckling on are varied-- all are photos, some brand new glossy color snap shots; and some on matte-finish older b & w photos, when I scan at 300 dpi.

Sasha