Flatbed scanner to place on top of paintings?

[Robert Montgomery]

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

Thanks, Chuck.

How could I put polazrizers over the sun?

Robert

 

[Neil Gould]

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

I'd recommend one of two approaches to accomplish this, neither of which
requires the kind of scanning that you're asking about.

Learn to take photos of your paintings using the techniques that MoiMoi
and others have presented. I wouldn't bother with stitching multiple
shots, because the printer's RIP is likely to downsample the file to 300 -
400 dpi anyway. That translates into a 10,800 x 14,400 dpi file to make a
36 x 48 print @ 300 dpi. This would suggest that a 4" x 5" camera could
easily produce superior results.

Continue to use the photographic and prepress departments to shoot your
artwork and prepare your files. The amount of time and effort that you'd
put in trying to get comparable results would likely more than pay for
their charges if you only value your time at minimum wage.

My $0.02...

Regards,

Neil

 

[Brendan R. Wehrung]

Thanks, Chuck.

How could I put polazrizers over the sun?

Robert

As I understand it, light from the sun is polarized, which is why polaroid
glasses work in the first place. They cancel out glare that's not in the
right plane. You can see for yourself by rotating the lens and watching
what you see change.

Brendan

 

[Barry Watzman]

I think that the solution to this is to get a "Roomba", a "hand scanner"
and 4 "electronic walls" and modify the Roomba to ............

 

[Barry Watzman]

Light from the sun is not polarized, it's reflection as glare is
polarized (sometimes)

 

[Robert Montgomery]

I'd recommend one of two approaches to accomplish this, neither of which
requires the kind of scanning that you're asking about.

Learn to take photos of your paintings using the techniques that MoiMoi
and others have presented. I wouldn't bother with stitching multiple
shots, because the printer's RIP is likely to downsample the file to 300 -
400 dpi anyway.

Thanks, Neil. I'm not using a RIP; I'm sending the files directly from
Photoshop to the printer drivers and then the printer drivers send the
files to the printers - without any RIPs.

I was told by the salesman of my Epson Stylus Photo 7600 wide-format
printer that the printer downsamples files to 200 dpi. (I'm setting my
printing resolution in my printer drivers to 720 dpi, but the printer
salesman said the printer can't process anything over 200 dpi.) Does
this make any sense?

That translates into a 10,800 x 14,400 dpi file to make a

36 x 48 print @ 300 dpi. This would suggest that a 4" x 5" camera could
easily produce superior results.

Can you recommend a four-by-five-inch camera that would be suitable for
photographing my paintings? Maybe I could use such a camera with natural
lighting on bright, cloudy days, to get suffused light, and thereby
not have to stitch together any images in Photoshop.

Continue to use the photographic and prepress departments to shoot your
artwork and prepare your files. The amount of time and effort that you'd
put in trying to get comparable results would likely more than pay for
their charges if you only value your time at minimum wage.

Neil

I thought that might be the case, after having mucked around with my own
digital photography and scanning of my paintings in the past, and having
had significant difficulties and mediocre to poor results.

Robert

 

[Robert Montgomery]

I think that the solution to this is to get a "Roomba", a "hand scanner"
and 4 "electronic walls" and modify the Roomba to ............

I don't understand. Wipikedia defines a roomba as "a robotic vacuum
cleaner made and sold by iRobot".

I think natural light - bright, cloudy days - would be easier to use
than buying and stetting up the LED panels that comprise 'electronic walls'.

Robert

 

[Robert Montgomery]

I think that the solution to this is to get a "Roomba", a "hand scanner"
and 4 "electronic walls" and modify the Roomba to ............

So there's no flatbed scanner that I could buy to scan my four-by-five
and eight-by-ten transparencies, that would equal the scanning quality
of the drum scanners used by the prepress companies?

Robert

 

[Neil Gould]

Thanks, Neil. I'm not using a RIP; I'm sending the files directly from
Photoshop to the printer drivers and then the printer drivers send the
files to the printers - without any RIPs.

I was told by the salesman of my Epson Stylus Photo 7600 wide-format
printer that the printer downsamples files to 200 dpi. (I'm setting my
printing resolution in my printer drivers to 720 dpi, but the printer
salesman said the printer can't process anything over 200 dpi.) Does
this make any sense?

What that means is that the printer is downsampling and printing your
image at a pixel resolution of 200 ppi. There is not much point in
exceeding that resolution in your captured image.

Can you recommend a four-by-five-inch camera that would be suitable
for photographing my paintings? Maybe I could use such a camera with
natural lighting on bright, cloudy days, to get suffused light, and
thereby not have to stitch together any images in Photoshop.

Any 4x5 inch camera would exceed your requirements by quite a bit.
However, since your workflow only requires 200 dpi, let's redo the math;
for a 36" x 48" print, you only need 7,200 by 9,600 dpi. That would result
in a file size a little over 69 megabytes. This is well within the range
of a medium format (6x6 or 6x7) camera and a reasonable film scanner.

I would still recommend an artificial light setup over natural light in
order to achieve consistency. I know it doesn't sound as "organic" as
using bright, cloudy days, but I think that is an excercise in frustration
if you want to control the results.

I thought that might be the case, after having mucked around with my
own digital photography and scanning of my paintings in the past, and
having had significant difficulties and mediocre to poor results.

Yes, there is much to know, especially if you are after top-notch results.
A medium format setup and film scanner is still quite an investment, and
the time to learn to use it would not be insignificant. Since you already
have the printer, I would highly recommend that you hire the pros to shoot
your artwork and create your files. Working on a buy-as-you-sell basis, it
would be hard to beat the costs by doing it all yourself.

Neil

 

[Neil Gould]

[...]
Continue to use the photographic and prepress departments to shoot
your artwork and prepare your files. The amount of time and effort
that you'd put in trying to get comparable results would likely
more than pay for their charges if you only value your time at
minimum wage.

So there's no flatbed scanner that I could buy to scan my four-by-five
and eight-by-ten transparencies, that would equal the scanning quality
of the drum scanners used by the prepress companies?

In a word, no. On the other hand, you may not require drum scans to
achieve image files suitable to your Epson 7600. There are several flatbed
scanners that could give you acceptable results at the 200 dpi that your
Epson printer delivers (even from Epson), but you will still be spending a
good deal of time in getting those results.

Neil

 

[thomas.c.monego]

So there's no flatbed scanner that I could buy to scan my four-by-five
and eight-by-ten transparencies, that would equal the scanning quality
of the drum scanners used by the prepress companies?

Robert

Sounds like you are not getting the best quality in your drum scans.
Right now Kodak Creo Eversmart scanners do about the best work, they
are flatbeds, if you can find a lab with one (used to be Sitex/Creo).
The latest Epson V700 or V750 should be able to give you scans of 4x5s
than equal the output of an Epson printer. These are far better than
your 1650 which was a middling scanner at best. Scanning the trannies
at 2400ppi in 16bits will give a 4-500 mb file that will directly
print the paintings. Try to keep the bit depth at 16bits per channel
and the ppi setting for the printer at 360 for Epson, 300 for Canon
and HP with out upsizing.
If you want to bypass scanning is to find a studio with a 4x5 scanning
back, Phase One and Betterlight make them. In recent tests the
scanning backs out resoved 4x5 film. Another is find a photographer
with the latest in MF digital backs, Hassleblad, Phase One or Imacon,
the 39mp ones are very close to 4x5 film.
If you want to photograph on a DSLR use a macro lens, 50 or 60mm
macros lenses are excellentfor this application. This is do to macro
lenses are flat field and have almost no distortions in the corners.
Both the Nikon and Canon macros are superb lenses.

Tom

 

[Robert Montgomery]

Sounds like you are not getting the best quality in your drum scans.
Right now Kodak Creo Eversmart scanners do about the best work, they
are flatbeds, if you can find a lab with one (used to be Sitex/Creo).
The latest Epson V700 or V750 should be able to give you scans of 4x5s
than equal the output of an Epson printer. These are far better than
your 1650 which was a middling scanner at best. Scanning the trannies
at 2400ppi in 16bits will give a 4-500 mb file that will directly
print the paintings. Try to keep the bit depth at 16bits per channel
and the ppi setting for the printer at 360 for Epson

Thanks, Tom and Neil.

Should the ppi setting for the printer be 360 even though the printer
downsampes to 200 ppi?

Also, I noticed in Photoshop that the drum scanned scans I've been
getting from my pre-press production company are only eight bits per
channel. Why is that and why do you recommend 16 bits per channel?

300 for Canon
and HP with out upsizing.
If you want to bypass scanning is to find a studio with a 4x5 scanning
back, Phase One and Betterlight make them. In recent tests the
scanning backs out resoved 4x5 film. Another is find a photographer
with the latest in MF digital backs, Hassleblad, Phase One or Imacon,
the 39mp ones are very close to 4x5 film.

I've been taking my paintings to a photographer who's using an Itoya
camera with a long bellows to shoot my paintings, but I'm trying to find
out here if it's feasible to avoid 'out-sourcing' the pre-press work.

If you want to photograph on a DSLR use a macro lens, 50 or 60mm
macros lenses are excellentfor this application. This is do to macro
lenses are flat field and have almost no distortions in the corners.
Both the Nikon and Canon macros are superb lenses.

Tom

How would the quality of a DSLR compare to a medium-format camera?

A friend of mine recently bought a ten-megapixel Canon EOS DSLR. Maybe I
could borrow it.

Rpbert

 

[Robert Montgomery]

Any 4x5 inch camera would exceed your requirements by quite a bit.
However, since your workflow only requires 200 dpi, let's redo the math;
for a 36" x 48" print, you only need 7,200 by 9,600 dpi. That would result
in a file size a little over 69 megabytes. This is well within the range
of a medium format (6x6 or 6x7) camera and a reasonable film scanner.

I would still recommend an artificial light setup over natural light in
order to achieve consistency. I know it doesn't sound as "organic" as
using bright, cloudy days, but I think that is an excercise in frustration
if you want to control the results.

Thanks, Neil. What kind of lighting?

Someone here recommended 'electronic walls', but that appears to be only
a prototype. I read this about 'electronic walls' on the Net: "ASSIST
and the LRC are pursuing avenues to advance the concept, including
collaboration with manufacturers to build a commercial product with a
standard, open architecture."

And this from another Web site: "In the future, homes and offices may
have electronic walls and ceilings that light up, and that can be
reconfigured with ease."

Robert

 

[Neil Gould]

Thanks, Neil. What kind of lighting?

You would need two diffuse light sources with a coverage larger than the
area of your painting. Given your 3'x4' paintings, this is not all that
difficult to do and could be built yourself very reasonably. For example,
many "do it yourself" stores offer halogen worklights on stands for about
$20 - $30 US. Go for about 500 - 600 watts per side, and make a stretched
canvas reflector painted flat white* to diffuse and bounce the light
toward your painting @ 45°. Adjust to suit after you see how the first
shots turn out.

* The color spectrum of halogen light is not quite the same as for
tungsten light bulbs, and also different films will produce a different
color balance on your paintings. You could adjust the color spectrum by
painting the panels off-white using a color that compensates for these
differences (shoot a standard photo target as a reference).

Neil

 

[Neil Gould]

Also, I noticed in Photoshop that the drum scanned scans I've been
getting from my pre-press production company are only eight bits per
channel. Why is that and why do you recommend 16 bits per channel?

16 bits/channel would allow more range for tweaking your scans, but it's
quite likely that your 7600 won't take those files directly. 8
bits/channel is a standard, and is likely to exceed the dynamic range of
your printer anyway.

How would the quality of a DSLR compare to a medium-format camera?

It doesn't. And, you can forget trying to get the same kind of results
you've been getting from 4x5 or 8x10 drum-scanned transparencies.

Neil

 

[Robert Montgomery]

You would need two diffuse light sources with a coverage larger than the
area of your painting. Given your 3'x4' paintings, this is not all that
difficult to do and could be built yourself very reasonably. For example,
many "do it yourself" stores offer halogen worklights on stands for about
$20 - $30 US. Go for about 500 - 600 watts per side, and make a stretched
canvas reflector painted flat white* to diffuse and bounce the light
toward your painting @ 45°. Adjust to suit after you see how the first
shots turn out.

* The color spectrum of halogen light is not quite the same as for
tungsten light bulbs, and also different films will produce a different
color balance on your paintings. You could adjust the color spectrum by
painting the panels off-white using a color that compensates for these
differences (shoot a standard photo target as a reference).

Neil

Thanks, Neil.

I can easily and quickly adjust color balance in Photoshop with the
Levels controller.

Also, I wouldn't need to paint reflectors white because stretched
canvases are already white. And a cheaper, more flexible and lighter
alternative to canvasses would be white templast or foamcore sheets.

Robert

 

[Neil Gould]

Thanks, Neil.

I can easily and quickly adjust color balance in Photoshop with the
Levels controller.

Well, you _can_ adjust the color balance that way, but it may not be
"easily and quickly". I still recommend that you adjust your lighting
until the color balance when shooting a standard target is as good as you
can get it. From that starting point, you can then tweak your color in
Photoshop. What I found when shooting artwork is that the process is an
interpretive art in itself. There may be colors in your paintings that
won't reproduce correctly in another medium and it will be up to you to
represent the essence of the work.

Also, I wouldn't need to paint reflectors white because stretched
canvases are already white. And a cheaper, more flexible and lighter
alternative to canvasses would be white templast or foamcore sheets.

The canvases I've seen appeared to be an off-white tending toward yellow,
but that may be due to my limited exposure to the range of products
available. The advantage of canvas over templast or foamcore is that the
textured surface of canvas diffuses the light better. But, it should be
inexpensive enough to try several materials and see what works best for
you.

Don't try to be too cheap on this... my light kit is in the 4 figure
range, and there are times when I still need to supplement it. However, I
think you can get by with a lot less for the single usage you have in
mind.

Regards,

Neil

 

[Robert Montgomery]

Well, you _can_ adjust the color balance that way, but it may not be
"easily and quickly". I still recommend that you adjust your lighting
until the color balance when shooting a standard target is as good as you
can get it. From that starting point, you can then tweak your color in
Photoshop. What I found when shooting artwork is that the process is an
interpretive art in itself. There may be colors in your paintings that
won't reproduce correctly in another medium and it will be up to you to
represent the essence of the work.



The canvases I've seen appeared to be an off-white tending toward yellow,
but that may be due to my limited exposure to the range of products
available. The advantage of canvas over templast or foamcore is that the
textured surface of canvas diffuses the light better. But, it should be
inexpensive enough to try several materials and see what works best for
you.

Don't try to be too cheap on this... my light kit is in the 4 figure
range, and there are times when I still need to supplement it. However, I
think you can get by with a lot less for the single usage you have in
mind.

Thanks, Neil.

I'm not planning on a single usage. At my current production rate, I'll
need to photograph at least a hundred paintings over the next 20
years, at a rate of about five paintings a year.


I emailed a local camera store about four-by-five cameras and the
recommendation was a Toyo camera, at a cost of about $5- to $6,000. That
cost is way beyond my budget, so I'm back to square one.

Even if I bought a used four-by-five camera at half that price, it's
more than I can afford now.

Robert

 

[Neil Gould]

Thanks, Neil.

I'm not planning on a single usage. At my current production rate,
I'll need to photograph at least a hundred paintings over the next
20 years, at a rate of about five paintings a year.

Forgive my pre-coffee post! I probably should have written "single
_purpose_", since I was referring to building a setup specifically to copy
your artwork, as opposed to a kit that would also be used for portraiture,
location shoots, etc.

I emailed a local camera store about four-by-five cameras and the
recommendation was a Toyo camera, at a cost of about $5- to $6,000.
That cost is way beyond my budget, so I'm back to square one.

As I mentioned before, a 4" x 5" camera greatly exceeds your needs. Since
your printer forces images to 200 dpi, a smaller medium format camera
would be more than adequate, and they are quite cheap these days. I'd
recommend something like a Pentax 67 (6cm x 7cm) which can be purchased
with a lens for under $500, or a Mamiya RB or RZ 67 for the same or a
little more.

Neil

 

[Jaqian]

Wht don't you just photograph it?

I had an old family portrait that I wanted a copy of but it was bigger
than my HP Scanjet 5530 (lid comes off) and stitching wasn't really
working. So in a well lit room (didn't use flash) I took about ten
photos of this picture which I then adjusted in GIMP and it worked
really well. Bit of advice... use a tripod.


Hope you get it sorted.

Jaqian