Scanner problems

[penguin32]

Hi,
I use a flatbed scanner to scan oil paintings so that I can make prints. This involves scanning the painting in small sections and then stitching the whole thing together with photoshop.
I first bought a Epson photo perfection V100 which is sort of ok image wise but then tried the latest version of scanner; the Epson perfection V37 which produced sharper brighter better coloured images.
All appeared well until I scanned a painting with even pale blue sky and then found banding in the scanning direction on the images. Dissasembly and inspection of the scanner shows the light source to be a row of LEDs which could be producing uneven illumination but does not quite match the pattern on the scanned image. The V100 has a tube light and gives even illumination. The problem only shows up in pale smooth images.

Any ideas on how to improve the v37 images?

PS not sure if this belongs in the general hardware forum

 

[JeffMD]

very interesting problem. You could attempt to create your own light spreader, however you may have to consider higher quality scanners designed for scanning art.

 

[corkyg]

I would do it this way rather than scan and stitch. Take a high res photo of the painting with a good camera and then deal with the jpg image for printing. I have an Epson V600 scanner, but would not even try what you are doing.

 

[JeffMD]

Corky, the dpi with a digital camera not costing thousands is inferior, also there is no lens distortion on a scanner. If your subject is flat, and you want to preserve details, scanners win hands down. They are still used religiously in many fields (course they aren't using $79 scanners off the shelf at best buy either).

 

[penguin32]

Hi Corkyg,

as JeffMD says a camera does not come close to a scanner for this sort of thing. For printing you need 300dpi and with a 24"x48" painting you soon run out of pixels. Also setting up lighting, camera angle, colour managment, exposure etc for a photo is very difficult. The stitching together with photoshop bit is fairly straight forward. Thanks for the thought though.

Jeff

can you recomend any models of scanner that would be suitable for this sort of work? the only art scanners I know of are cruise scanners.
Any ideas on how to make a light spreader? or links to good sites on scanners

thanks for the help

 

[corkyg]

These data tables might be of interest. As you get into top quality for commercial repro, things get expensive. The Epson Expression scanner is an example. You're looking at $2700 in round numbers. I understand the need for 300 DPI printing. I use my full frame Canon 5D MK !!, tripod, and balanced lighting. I deal with pixels in RAW format - tens of thousands.

http://www.chromatics.com/Scan_Cruse.htm

 

[JeffMD]

Peng, unfortunately Im not sure what you could do for a defuser in such a small area. You would need to get creative. On the basic side, cutting a strip of transluscent white plastic, on the creative side, design and print using a 3d printer a diffuse that funnels each led light outwards.

 

[ronbo613]

Im not sure what you could do for a defuser in such a small area.

If the light are LEDs, use a paper towel.

 

[penguin32]

Hi Corky
Thanks for the links, thats the first time i have come across the canon expression scanner, though as you say not cheap. I may have to bite the bullit and send my paintings for professional scanning on a cruise machine. I wish there was a machine near where i live as im some what frightend of shipping artwork.
We have an Eos7D (19mpix) around the house an i estimate you can take a 12x17 inch picture at 300dpi roughly. So our 7D is not really up to imaging 24x36 inch paintings and I can never get the lighting right.

Jeff and ronbo

I will have a go at simple light diffusers I had not thought of that before, as you say get creative.

Peng

 

[Jubassi]

300dpi scanners always give me some problems. Make sure the drivers are good and windows updated