Re: [Gimp-user] Fw: scan-mirrage-effect-Problem with postcard

[Ofnuts <ofnuts gmx com>]

If the moiré isn't the same when you do several scans (after moving the
card a bit), then you can eliminate the moiré by making several scans
and averaging them after making them overlap exactly.

To average images you can stack them and set the opacity to 100/N where
N is the order of the layer in the stack starting from the bottom: 100%
at the bottom, then 50%, then 33%, 25%, 20%, 17%... There is also a
average filter in the GMIC plugin (but the median filter it contains may
be even better).


On 11/05/2021 02:56, Rick Strong wrote:
> I didn't see my reply show up on the Gimp user list.
> RS
> -----Original Message----- From: Rick Strong
> Sent: Monday, May 10, 2021 11:33 AM
> To: Tim (from Hamburg) ; gimp-user-list gnome org
> Subject: Re: [Gimp-user] scan-mirrage-effect-Problem with postcard
>
> Well, it's not moiré from the glass.
>
> It seems to be a scanning artefact introduced by the scanner. But you
> say it
> doesn't happen with scans of images on plain or matte paper.
> try putting a black card over the postcard before you lower the lid. Also
> check your scanner settings.
>
> If that doesn't work, you could try photographing the glossy postcard
> with a
> camera. With some fridge magnets you could stick it vertically to the
> side
> of something metallic in good light, like your refrigerator or your car.
> Then crop out or clone out the magnets from the photograph.
>
> Rick S.
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