About white dots(arti-fact) and noise

[kimiraikkonen]

I'm using Canon All-in-one Pixma MP830 scanner and have to ask
something which are weird.

Although the scan glass is clean, even there's no much dust or dirt
under the glass, when i scan good and clean photos using its software
MP Navigator or another softwares, i usually get a lot of "white dots"
which are patterned randomly on the image area. I used ScanGear MP of
Canon which is official Twain of Canon, selected dust removal or
reduction but it wasn't much effective.

Why are there white dots on the scanned image although glass is clean
and original photo is fine?

Could you explain it technically? Is it common or usual or is it a
reason to return the scanner back?

Besides white dots, as usual noises are present, but i wonder these
strange white dots and dirt displayed after scanning a high-DPI and
high-quality image?...

Please explain...

Regards.

 

[Bruce]

I'm using Canon All-in-one Pixma MP830 scanner and have to ask
something which are weird.

Although the scan glass is clean, even there's no much dust or dirt
under the glass, when i scan good and clean photos using its software
MP Navigator or another softwares, i usually get a lot of "white dots"
which are patterned randomly on the image area. I used ScanGear MP of
Canon which is official Twain of Canon, selected dust removal or
reduction but it wasn't much effective.

Why are there white dots on the scanned image although glass is clean
and original photo is fine?

Could you explain it technically? Is it common or usual or is it a
reason to return the scanner back?

Besides white dots, as usual noises are present, but i wonder these
strange white dots and dirt displayed after scanning a high-DPI and
high-quality image?...

Please explain...

Regards.

What do these dot look like? Was the original textured?

 

[Barry Watzman]

Clean the glass. Clean the photo. You MAY have to take the scanner
apart and clean the INSIDE of the glass (dust is possible on the
sensors also, but it will show up as lines, not specs).

Ultimately, it's just about impossible to get totally dust free scans of
photos, so then you have to use a photo editor to touch it up. You can
do this by hand (can take minutes to an hour per photo) or with a "dust
filter" in the photo, but the dust filter usually slightly degrades
detail in the image.

 

[MoiMoi]

I'm using Canon All-in-one Pixma MP830 scanner and have to ask
something which are weird.

Although the scan glass is clean, even there's no much dust or dirt
under the glass, when i scan good and clean photos using its software
MP Navigator or another softwares, i usually get a lot of "white dots"
which are patterned randomly on the image area. I used ScanGear MP of
Canon which is official Twain of Canon, selected dust removal or
reduction but it wasn't much effective.

Why are there white dots on the scanned image although glass is clean
and original photo is fine?

Could you explain it technically? Is it common or usual or is it a
reason to return the scanner back?

Besides white dots, as usual noises are present, but i wonder these
strange white dots and dirt displayed after scanning a high-DPI and
high-quality image?...

Please explain...

Regards.

ALL prints have dust specks recorded in the image.
They show up as white, same as if you scanned a negative.
(dust on slides shows as black).

Some worse than others, but even "pro" prints do too.
Take a loupe and look at the print at 8x magnification or so.
You'll see.

To prove it to yourself, turn the print around and make two scans.
Look on same area of the two scans, you'll almost certainly find
corresponding specks.

MM

 

[kimiraikkonen]

Hi, sorry for late reply,
The white dots or some scratches appear if you view the image in
orginal size (full size) but the picture and scanning plate is clean
enough not to display that kind of white dots. Are they dirts or arti-
facts?

How to make out arti-facts of scanning seperated from dirts?

Please show some examples...

Thanks.

 

[Barry Watzman]

They are probably dust