Help: scanner fault?

[Tony B]

I hope someone can shed some light on this problem.

I am scanning Fuji Velvia on an Epson 750, using Epson scan at 2400dpi. The view is of Carsington Water at sunset and the far bank is in deep shadow, almost black, as a band across the image. In this area of deep shadow I can clearly see a network of horizontal and vertical bars, breaking the deep shadows into various sizes of rectangle. The bars are slightly lighter than the deep shadow. There is no repeat pattern present; just the random network of vertical and horizontal bars over the entire shadow area. This is present on two separate images, so is not specific to just one transparency.

The pattern is not evident on a lightbox. When viewing in photoshop, I can make the pattern even clearer when I lighten the area with levels, to dispel all doubt that the effect is there.

Is this a technique, or equipment problem? Has anyone had a similar effect?

Tony

[Patrick Dixon]

Make sure you aren't covering the calibration area of the scanner glass at the end near to the hinge. Check the cutouts in the Epson holders to see where it is if you are not sure.

[dave_whatever]

I have used a v700 that had banding in deep shaddows, but it was a regular pattern.

Can you post up an example?

[Tony B]

Hello

I hope this uploads correctly.

This is a small section of the whole image. To illustrate the pattern effect, I have darkened the image by adjusting the levels, and taken a screen shot. It shows the pattern very clearly. At normal brightness levels, this pattern is only apparent in the deep shadow areas, but is clearly there in latent form over the scan.

I would also add that the pattern only appears when the image is magnifies; at normal viewing the pattern is not obvious.

Tony