Flatbed scanner to place on top of paintings?

[Robert Montgomery]

Is there a flatbed scanner with decent resolution that I can place on
top of my paintings so that I can scan my paintings in sections and then
stitch together the scanned files in Photoshop?

Robert

 

[MoiMoi]

Is there a flatbed scanner with decent resolution that I can place on
top of my paintings so that I can scan my paintings in sections and then
stitch together the scanned files in Photoshop?

Robert

Two word answers:
Digital camera.
Even lighting.
Tri Pod

MM

 

[Neil Gould]

Is there a flatbed scanner with decent resolution that I can place on
top of my paintings so that I can scan my paintings in sections and
then stitch together the scanned files in Photoshop?

The technique is questionable -- it might be wiser to put your paintings
on top of the scanner. As for the resolution, almost any flatbed will
exceed what you can realistically use.

Neil

 

[Brendan R. Wehrung]

The technique is questionable -- it might be wiser to put your paintings
on top of the scanner. As for the resolution, almost any flatbed will
exceed what you can realistically use.

Neil

I don't think it's made any more (although you might see it on CSI Miami),
but I have one of these and have laid a large map on the floor and
stitched together multiple scans it as you describe.

http://h20271.www2.hp.com/SMB-AP/cache/121278-0-0-190-121.html

The scanner is in the top (or left) half), the bottom is just t0 hold the
copy. Or you can lay it on something larger like a newspaper page or map.

Possibly still available via eBay.

Brendan

 

[Robert Montgomery]

I don't think it's made any more (although you might see it on CSI Miami),
but I have one of these and have laid a large map on the floor and
stitched together multiple scans it as you describe.

http://h20271.www2.hp.com/SMB-AP/cache/121278-0-0-190-121.html

The scanner is in the top (or left) half), the bottom is just t0 hold the
copy. Or you can lay it on something larger like a newspaper page or map.

Possibly still available via eBay.

Brendan

That scanner isn't made anymore and my paintings are too big and thick
to fit into it anyway (one and-a-half inch stretcher bars).

I tried photographing the paintings in sections but the results are
terrible. It's hard to avoid unwanted highlights, distortion and
inconssistent colors among the stitched photos.

Robert

 

[MoiMoi]

That scanner isn't made anymore and my paintings are too big and thick
to fit into it anyway (one and-a-half inch stretcher bars).

I tried photographing the paintings in sections but the results are
terrible. It's hard to avoid unwanted highlights, distortion and
inconssistent colors among the stitched photos.

Robert

You need a basic understanding of copy photography/lighting.
Exact controllable 45 degree lighting, no wider than 50mm on lens zoom
and of course exact same focal length setting for each shot so that
later stiching doesn't bring in ppi variables to make it harder, tripod
to get exactly square to the middle of the section you are copying,
cardboard lens "cheater" for any stray glare, etc. It's quite doable and
most important, repeatable.
If you have a lot of these to do, perhaps worth it to go to a pro copy
place that has a large wall copy setup and see just how it's done, even
if you have to pay for some look-see time.

It's really unlikely you'll ever be pleased with any kind of flat-bed
setup for this.

Another possiblility is to have 4x5 film trannies shot by a pro copy
place and scan them.

MM

 

[Brendan R. Wehrung]

That scanner isn't made anymore and my paintings are too big and thick
to fit into it anyway (one and-a-half inch stretcher bars).

I guess I didn't explain clearly enough. Only the left portion is
actually active. It's a sandwich of glass with the scanner element and
lights running in between. Canvas on a stretcher might be a problem
unless backed up with something firm but the other (right or bottom) part
of the unit is just a holder and I've never used it. It's like laying a
framed piece of 8 1/2 x 11 glass on a open book, looking through the glass
at what you wish to scan and pressing the button. You don't put anything
"in" it.

I tried photographing the paintings in sections but the results are
terrible. It's hard to avoid unwanted highlights, distortion and
inconssistent colors among the stitched photos.

Robert

I'll bet professional photo houses would make digital images for you of
the entire canvas, but file size would be so large most photo editing
software would choke on them if you tried to reduce the original. $$$
too.

As for highlights, you need to make a "light tent" (a scrim in front of
the lights tht makes a large, non-point light source, or through a thin
bed sheet); flat lighting doesn't have highlights and is used a lot for
portraits. But you still have to get even lighting across the entire
canvas.

Out of curiousity, how large is the final print you want to make? Even
point and shoot cameras these days can run 7 megapixels and that ought to
make a decent 16 x 20 print.

Brendan

 

[Peter Finney]

I tried photographing the paintings in sections but the results are
terrible. It's hard to avoid unwanted highlights, distortion and
inconssistent colors among the stitched photos.

You can avoid the highlights by careful lighting.

The other problems can be largely overcome by using a decent stitching
program (I use Panavue Image Assembler for this type of use).

The makers of AutoPano Pro have an orthographic mode on their 'to do'
list. This would be an ideal solution - but there is no knowing when
it will happen.

Having said all that - it can be time-consuming (in the photographic
setup).




Peter Finney
Liphook
Hampshire
England

 

[Tim]

You need a basic understanding of copy photography/lighting.
Exact controllable 45 degree lighting, no wider than 50mm on lens zoom
and of course exact same focal length setting for each shot so that
later stiching doesn't bring in ppi variables to make it harder, tripod
to get exactly square to the middle of the section you are copying,
cardboard lens "cheater" for any stray glare, etc. It's quite doable and
most important, repeatable.

I once tried flatbed scanning some old maps, but it was horribly awkward
and damaged the maps. Eventually I used the technique described by
MoiMoi. You don't necessarily need professional lights, but it does
need to set up carefully. Quartz-halogen bulbs may be better than
ordinary lamps to bring out the blue tones.

You also need a good camera and a good lens (preferably fixed focus).
Exposure, focus, and white-balance all need to be fixed. To stitch the
photos, you'll need half a frame overlap between each image, and some
good blending software. I use Hugin and Enblend (both free).

Tim

 

[Robert Montgomery]

You need a basic understanding of copy photography/lighting.
Exact controllable 45 degree lighting, no wider than 50mm on lens zoom
and of course exact same focal length setting for each shot so that
later stiching doesn't bring in ppi variables to make it harder, tripod
to get exactly square to the middle of the section you are copying,
cardboard lens "cheater" for any stray glare, etc. It's quite doable and
most important, repeatable.
If you have a lot of these to do, perhaps worth it to go to a pro copy
place that has a large wall copy setup and see just how it's done, even
if you have to pay for some look-see time.

It's really unlikely you'll ever be pleased with any kind of flat-bed
setup for this.

Another possiblility is to have 4x5 film trannies shot by a pro copy
place and scan them.

MM

I've been getting four-by-five and eight-by-ten trannies made for many
years, but my scanner issn't good enough to scan them.

I have an Epson Perfection 1650 scanner, which, despite its name, is
not perfect for the job.

I was told that I'd need to buy a drum scanner to do the job to a
professional level, and those drum scanners are big, bulky, heavy and
expensive. My studio is small and crowded, so I don't have enough room
for another big piece of equipment.

I've been taking my trannies to a pre-press production company for drum
scanning, but contracting out the professional photography of the
paintings and subsequent drum scanning of the trannies is expensive.

Robert

 

[Robert Montgomery]

I guess I didn't explain clearly enough. Only the left portion is
actually active. It's a sandwich of glass with the scanner element and
lights running in between. Canvas on a stretcher might be a problem
unless backed up with something firm but the other (right or bottom) part
of the unit is just a holder and I've never used it. It's like laying a
framed piece of 8 1/2 x 11 glass on a open book, looking through the glass
at what you wish to scan and pressing the button. You don't put anything
"in" it.





I'll bet professional photo houses would make digital images for you of
the entire canvas, but file size would be so large most photo editing
software would choke on them if you tried to reduce the original. $$$
too.

I tried that, but the results were mediocre. The head of the pre-press
production company boasted that he had spent hundreds of thousands of
dollars on a state-of-the art scanner, but there was considerable
drop-off of the light at the edge of the scans because my paintings are
big and there's only one light at the top of the flatbed scanner.

I've concluded that if it's a flatbed scanner, it should have two lights
to avoid drop-off of light at the edges and to avoid highlights and
shadows where the bumps of paint occur on the canvasses. (Like when the
pro photographer photographs my paintings, he has a light on each side
of the painting to get even light and minimize highlights and shadows.)

As for highlights, you need to make a "light tent" (a scrim in front of
the lights tht makes a large, non-point light source, or through a thin
bed sheet); flat lighting doesn't have highlights and is used a lot for
portraits. But you still have to get even lighting across the entire
canvas.

I think I'll skip trying again to photograph the paintings myself
because I'm so inept at mechanical tasks like that.

Out of curiousity, how large is the final print you want to make?

They're about as big as 22 by 29 inches.

Even

point and shoot cameras these days can run 7 megapixels and that ought to
make a decent 16 x 20 print.

Brendan

Robert

 

[Robert Montgomery]

You can avoid the highlights by careful lighting.

The other problems can be largely overcome by using a decent stitching
program (I use Panavue Image Assembler for this type of use).

The makers of AutoPano Pro have an orthographic mode on their 'to do'
list. This would be an ideal solution - but there is no knowing when
it will happen.

Having said all that - it can be time-consuming (in the photographic
setup).

Yes, that's what I found. It's painstaking work – especially for the big
paintings I'm working on, which are each about three by four feet.

Robert

 

[Robert Montgomery]

You need a basic understanding of copy photography/lighting.
Exact controllable 45 degree lighting, no wider than 50mm on lens zoom
and of course exact same focal length setting for each shot so that
later stiching doesn't bring in ppi variables to make it harder, tripod
to get exactly square to the middle of the section you are copying,
cardboard lens "cheater" for any stray glare, etc. It's quite doable and
most important, repeatable.
If you have a lot of these to do, perhaps worth it to go to a pro copy
place that has a large wall copy setup and see just how it's done, even
if you have to pay for some look-see time.

It's really unlikely you'll ever be pleased with any kind of flat-bed
setup for this.

I was looking at the Colortrac Flatbed 24120 on the Internet, which are
pro quality scanners that can scan paintings up to 24 by 36 inches in
one scan, (http://www.colortrac.com/case_studies/k_wyatt.htm) but the
scanners are massive and I don't have enough room in my small studio,
and based on the size, I wouldn't be surprised if they cost $10,000. (I
haven't been able to find a price on them yet. I emailed Colortrac but
no one answered and the price isn't listed on the Colortrac Web site.)

Another possiblility is to have 4x5 film trannies shot by a pro copy
place and scan them.

MM

That's what I've been doing for many years but I wonder if I could do at
least part of the work myself to save money.

Robert

 

[Robert Montgomery]

I once tried flatbed scanning some old maps, but it was horribly awkward
and damaged the maps. Eventually I used the technique described by
MoiMoi. You don't necessarily need professional lights, but it does
need to set up carefully. Quartz-halogen bulbs may be better than
ordinary lamps to bring out the blue tones.

You also need a good camera and a good lens (preferably fixed focus).
Exposure, focus, and white-balance all need to be fixed. To stitch the
photos, you'll need half a frame overlap between each image, and some
good blending software. I use Hugin and Enblend (both free).

Tim

Thanks, Tim.

I tried Hugin and Embed because of your recommendation.

Hugin is the type of program suited for technical people like computer
programmers. It's not suited to people like me, who are artistically
oriented, rather than technically oriented. It's not 'user friendly', as
they say.

I couldn't even open the copies of Embed that I downloaded. The Emblend
site leads to the X Blend for Mac OS X Web site. There I downloaded X
Blend for Mac OS X. Every time I click on the X Blend icon, my Terminal
program opens insteade, with a cryptic message in the Termainal window.
I emailed the Krekus.com Web site for assistance, and I'm waiting for an
answer.

Robert

 

[MoiMoi]

I've been getting four-by-five and eight-by-ten trannies made for many
years, but my scanner issn't good enough to scan them.

I have an Epson Perfection 1650 scanner, which, despite its name, is
not perfect for the job.

I was told that I'd need to buy a drum scanner to do the job to a
professional level, and those drum scanners are big, bulky, heavy and
expensive. My studio is small and crowded, so I don't have enough room
for another big piece of equipment.

I've been taking my trannies to a pre-press production company for drum
scanning, but contracting out the professional photography of the
paintings and subsequent drum scanning of the trannies is expensive.

Robert

Flat beds have improved quite a bit since when the 1650 came out.
Though film scanners are certainly much better for 35mm (and even 120
film), 4x5 and larger trannies can be rendered very well by some
affordable flatbeds. I haven't kept up with just what scanner models do
what max size transparency, but surely there's one that would do rather
nicely?

MM

 

[Brendan R. Wehrung]

I tried that, but the results were mediocre. The head of the pre-press
production company boasted that he had spent hundreds of thousands of
dollars on a state-of-the art scanner, but there was considerable
drop-off of the light at the edge of the scans because my paintings are
big and there's only one light at the top of the flatbed scanner.

I've concluded that if it's a flatbed scanner, it should have two lights
to avoid drop-off of light at the edges and to avoid highlights and
shadows where the bumps of paint occur on the canvasses. (Like when the
pro photographer photographs my paintings, he has a light on each side
of the painting to get even light and minimize highlights and shadows.)

I think I'll skip trying again to photograph the paintings myself
because I'm so inept at mechanical tasks like that.


They're about as big as 22 by 29 inches.

Even

Robert

I forget one solution that often works very well, cloudy daylight. If the
goal is to minimize highlights, caused by small (pinpoint) light sources
bouncing off differences in texture, spread the light out, using a bank of
clouds that diffuses the sun.

Choose a day that's "cloudy brihgt" (solid overcast but not too dark) and
set your camera on a tripod. As you will have found out it is important
to set the camera up so there is minimal keystoning (perspective causing
parallel lines to converge), important for both stitching and not having
to do a lot of straigntening out later.

If you insist on shooting portions instead of the entire canvas, once you
have a non-keystoning setup, consider moving the painting instead of the
camera, shifting from side to side and using props of various heights for
lower, middle and top portions.

You will find that there will be a different color shift (towards blue)
from inside that may have to be compensated for, depending on how well your
camera balances white.

Brendan

 

[Chuck Tribolet]

The trick to avoiding specular highlights is polarization. You use a polarizing filter on both
the ligh source and the lens. IIRC, you orient them at 90 degrees to each other. But just
play with the angles and see what works best.

Edmund Scientific has sheets of polarizing material.


Chuck Tribolet

 

[Neil Gould]

I've been getting four-by-five and eight-by-ten trannies made for many
years, but my scanner issn't good enough to scan them.

I have an Epson Perfection 1650 scanner, which, despite its name, is
not perfect for the job.

I was told that I'd need to buy a drum scanner to do the job to a
professional level, and those drum scanners are big, bulky, heavy and
expensive. My studio is small and crowded, so I don't have enough room
for another big piece of equipment.

I've been taking my trannies to a pre-press production company for
drum scanning, but contracting out the professional photography of the
paintings and subsequent drum scanning of the trannies is expensive.

All of this begs the question, what are you planning to do with the scans?
Are you just documenting your work? Planning on producing a catalog? The
answers would help a lot in making recommendations.

Neil

 

[Robert Montgomery]

All of this begs the question, what are you planning to do with the scans?
Are you just documenting your work? Planning on producing a catalog? The
answers would help a lot in making recommendations.

Neil

Making art prints on paper (giclées, to be specific) to sell to art
galleries. So the quality must be superior.

Robert

 

[Robert Montgomery]

I forget one solution that often works very well, cloudy daylight. If the
goal is to minimize highlights, caused by small (pinpoint) light sources
bouncing off differences in texture, spread the light out, using a bank of
clouds that diffuses the sun.

Choose a day that's "cloudy brihgt" (solid overcast but not too dark) and
set your camera on a tripod. As you will have found out it is important
to set the camera up so there is minimal keystoning (perspective causing
parallel lines to converge), important for both stitching and not having
to do a lot of straigntening out later.

If you insist on shooting portions instead of the entire canvas,

Thanks, Brendan. I just experimented. I made a photo at the maximum
resolution that my camera allows, and uploaded it to my computer. The
TIFF file takes up 11.2 megabytes. The files I've been getting from the
pre-press production company are 175 megabytes.

So I calculate that I'd have to make about 16 photos at my camera's
maximum resolution to cobble together one big file that's about 175
megabytes in size.

That shows that it's not possible for me to make only one photo of a
painting and have as much detail in that photo as in the drum scan
TIFFs. It means that my best photos contain only about one-sixteenth of
the data that's in one of the drum-scanned TIFFs.

Robert