Scanning, scanning, scanning

This installment of Ripped from the List reviews three recent listserv threads that dealt with techniques for converting traditional art to digital media, preliminary considerations, and subsequent manipulations of the scanned images.

Scanning Large Artwork

Rick L. Simonson: Does anyone have a good method for getting large (maybe 24” x 36”) traditional artwork into the computer? Scanning seems like a good idea, unfortunately, large format scanners are quite expensive. I suppose I could scan it multiple times and stitch it together in Photoshop. Or send it to a large format scanning service?

I’m not sure if photographing the artwork would produce good results. I’m sure a lot of people do this. What is the best method? Any ideas?

Kathleen Garness: I have limited experience scanning larger images in Photoshop® and ‘stitching’ them together with varying degrees of efficacy. For some reason there is occasional variance (even though I don’t touch the settings!) in the scan and save, so the ele-ments don’t quite fit together perfectly.

I have heard that taking a photo with a 100mm telephoto lens, and using a copystand, offers excellent results. I haven’t yet hired anyone to do this for me but I know that high-quality photo labs will provide this service for a fee.

Frank Ippolito: Copy photography. Using pro lighting and a hi-res camera is the way to go. this is how traditional artwork was reproduced for decades before the rise of digital scanners. the key is even light-ing—which is even more essential if working in a transparent medium.

Anne Runyon: Frank, can you explain what copy photography is? Why better than scanning of some sort? (This leads me to also ask, what is intended use of the digital file to be?)

Frank Ippolito: By copy photography, I am referring to shooting the art using a copy stand and matched lighting. the camera mount is essentially a monopod mounted to a table surface. Ideally, the lighting is mounted in a fixed array, which offers the most predictable results. larger work might require the use of a tripod outfitted with a special head that will position the camera’s “film plane” parallel with the tabletop (or floor) as Kathleen mentioned, a portrait focal length (80 to 120 mm) is required to avoid any distor-tion. when working with lighting that is not in a fixed array (which would have been pre-positioned for even spread, be sure to keep the lights far enough away to avoid any hotspots.

I googled copystand and found this little photo blog that had a few examples etc.:

Kathleen Garness: May I offer another small addition to the discussion? Copy shops and professional film studios use color-balanced lighting, the setup of which can be expensive in dollars and space, so it’s often very worthwhile to go that way rather than try to set it up oneself.

And thanks, Anne, for mentioning drum scanners. Those are still in use in large shops and, as you say, give excellent results for large, flexible surfaces; they were a mainstay of the large advertising arts stu-dio, back in the day ; ), and still might be!

Gail Guth: I have a legal-size scanner (8.5 x 14) and I scan art in sections. I used to go bit-by-bit and line it all up (that can be tricky). Photoshop (CS3 & 4, maybe earlier verisons too) has a feature called Photomerge I just discovered that works surprisingly well and very fast:

[File-->Automate-->Photomerge in CS4]

I try to make the breaks in areas where it’s less likely to show, either blank areas or very busy ones, like areas of grass or trees or lots of feathers; I avoid the key parts of the art. I also try to include a bit of each section in the next one for alignment purposes. It’s important to try to keep the sections square with the scan bed, as rotating the images after scanning causes all sorts of problems. Sometimes you can’t help but get them out of alignment, though.

If I’m doing it the “old-fashioned” way, I combine the multiple scans in one layered document, then move the image around one layer at a time, dimming the layer I’m moving to around 50% so I can easily see when it’s lining up correctly. When they are lined up I adjust the levels or brightness or whatever else needs adjusting between the layers, then flatten the whole thing. If needed you can zoom in and clean up with a little selective cloning or other adjustments.

Tedious but it works. If you can, try Photomerge, so PShop does most/all of that work for you.

Barbara Harmon: I have used all the aforementioned methods. To me, it depends on the use. If you want a close-to-perfect reproduction (e.g., fine art for print/giclee) then I have my printer (service, not device) scan it (which will be necessary for the giclee anyway), and I also ask for a digital file on CD. I have also used a local professional photographer with copy stand setup (up to very large sizes), just like what Frank suggests (fixed array or otherwise very specific lighting and distortion controls) where I also end up with a CD. Both have produced perfect results, but add an expense.

If I am using the art for illustration then I either scan and stitch, or photograph with my own digital SLR. These methods are imperfect but since I will end up manipulating in Photoshop® anyway it doesn’t matter. Scanning and stitching are more time-consuming and I will decide which way to go based on that (time), size, and use. Good luck!

Britt Griswold: This is really a multifaceted area to explore. Prepress shops often have a flatbed scanner that can take 30 inch copy.

Prepress shops that specialize in fine art reproduction may have digital stu- dio cameras that are set up as Frank suggests, and can shoot 300MB files or higher of large Art.

A long lens (105-130) on a good digital camera, with good lighting, will do a decent job.

Color balance of the light is important, but can be edited with proper calibration. A cool bit of software I just acquired can be used with a portable swatch palette to capture the lighting en- vironment and convert it into a light pro- file to apply to your digital files captured in the same environment (x-Rite Color Checker passport) It works with Digital cameras that capture RAW format.

And of course, Gail’s method of scan and pan is one I have used as well. The Photoshop® stitcher sounds useful!

Barbara Gleason: When I get something like this that’s larger than I care to try to stitch together in Photoshop®, I’ve got col- leagues who do giclée work for artists and typically, such folks tend to have larger scanners than most of us do. It might be worth checking who locally has a larger scanner, and such a place might be a good bet!

Good luck... I usually stitch things if doing so means only about 4-6 pieces. More than that and it can get dicey to line the pieces up!

Bruce Bartrug: Barb, that’s a really good suggestion. The process is expensive, but the results are superb. I have the same sort of relationship with a print maker, and they have a scanner that does fairly large pieces, at least 3 x 4 feet. I can’t imagine what a scanner like that cost, but its great having one around when it’s needed.

Linda Feltner: It’s a good point comparing your time to spend $75-$85 bucks on a good digital capture (300-500MB) vs. splicing and adjusting levels, etc yourself. Especially when working with watercolor or any transparent media.

A lot of my work is 24"x36”’ sometimes 32”x40”. I’ll use a printing service in Tucson every time. This couple are optical engineers and giclée print/photographer specialists, never met better. They bought a digital capture camera that captures 40"x65” and larger pieces. The cameras are really expensive, heck, the light “bulbs” are about $5K each. Before they bought their camera I used another service in town that did not replace both “bulbs” when one went out, so just like on the setup that Frank mentioned (a copy station) if one bulb is weak, it will not have the same color balance or strength that the fresh one will.

The result is uneven white backgrounds from one side to the next. When you pay $75 for a capture, only to find you have to spend two hours balancing the whites from one side of the piece to the other, well, that’s time and money lost. That’s one reason these folks purchased their own digital capture camera, they have perfect control. So all digital capture shops are not the same.

When doing small pieces, I use my legal-sized flatbed scanner in my office. For only drafts of these huge pieces I will splice the large piece quickly, but for the final art, I’ll get the capture done.

Gretchen Halpert: Pre-scanning era, I always photographed on a copy stand with excellent results. Now I scan when possible. When it’s too large for my scanner, I go to the copystand which has balance lighting. Too large for the copystand, I photograph outside in diffused lighting. My results depend on what I am photographing. Paintings work well. Pen and ink, and especially scratchboard, are a challenge using both a scanner and digital camera. I love my digital camera, but I still haven’t gotten my results as perfect as I had with film… so then I take it into Photoshop.


Scanning Graphite Drawings

Bruce Bartrug: …does anyone know a technique for getting decent scans of regular old graphite sketches and drawings? The reason for asking is that I’d like to scan sketches and “ink” them on a layer in Photoshop using the Intuos pad I have. But graphite just doesn’t scan very well on my Microtek S400. I’ve adjusted the 0-255 values slider (Levels in Photoshop) to darken the lines, and also changed the response line slope, but that still doesn’t get the lighter lines. My only recourse is to ink the drawing on paper then scan same and do corrections using the Intuos. If I’m going to do that, however, I might as well just transfer the sketch to a piece of Bristol and do the ink by hand. Of course, I wouldn’t be able to eliminate mistakes instantly either…

Clara Richardson: I can’t say anything about your scanner, but I use 2 Epson scanners (depending on location) and have no trouble at all getting nice scans of pencil work that are completely readable (and sometimes printable on their own). The key is the software. Both places have Silverfast as the scanner software and it allows all sorts of curves and levels adjustments to the prescan—similar to the PS interface—so all your pixels are where you want them to be in the actual scan (if you do the adjustment in PS after the scan you waste a lot of pixels).

Will Smith: I can’t understand why you can’t get pencil lines. Are you sure you have your scanner on greyscale and not black and white??

Bruce Bartrug: Actually, Will, using “line drawing” works better with pencil than greyscale. I still have to dial the dark slider up to over 200 (on the 0 to 255 scale) to get a decent scan. It’s annoying, and the scans are noisy, but I guess I’ll just make do.

Will Smith: You’ve got me wondering, as I am doing this all the time. In what way better?

Bruce Bartrug: In my case, the lines scan more clearly, and it’s easier to eliminate some of the noise associated with dialing the slider way up to get usable scanned lines. That could be related to the “line drawing” scan method being a 1-bitmap type image? Not sure. I should indicate that I sketch with HB or 2H leads, and draw best with light strokes. I’ve tried softer leads but I hate to sharpen so often. Just lazy I guess.

Will Smith: I guess we all skin cats differently. I mostly also use HB pencils. I eliminate noise in Photoshop and use the tracing process to achieve clean flowing lines. I sometimes convert the sketch to a colour to help the tracing stand out from the sketch. Thanks for sharing the way you work.

Clara Richardson: Bruce - oh, I use darker leads than that - partly I suppose because of the scanning thing.

But you should be able to tell the scanner software to only register the grays between the background and the pencil line and stretch the values out in the process. Curves, sliders, contrast, brightness, all those tools should be in the scanner software.

Britt once said to me that the whole deal with scanners isn’t the hardware anymore, it’s the software. I suppose you could try a color scan which might pick up more subtlety and then convert it to grayscale in PS.

Bruce Bartrug: Thanks, Clara. I was indeed scanning in RGB, as I thought it easier to pick up subtle values as you mentioned, but switched to line drawings in desperation and that helped considerably. Not perfect but certainly usable, and truly that’s all I need.


Line Art Scanning

Marjorie Leggitt: I have a technical question concerning a several museum panels I am creating. I’m working on several exhibit illustrations, the base art of each are being created as traditional pen and ink on frosted mylar at 25-30% final size. I’ll be adding color in Photoshop.

Scanning—What is the best way to scan the base line art (on frosted mylar) as it will be imported into Photoshop? (I planned on scanning at 1200dpi so that final art will be 300dpi.) Is it best to scan as grayscale then convert to color OR as bit-map? Any advise will be greatly appreciated.

Linda Feltner: I usually scan at grayscale, and work in RGB in PShop. Then when the colorizing is complete, convert it to CYMK. It may not be the best way to go (there are folks on the Listserv who know a lot more than I), but this method has, at least, given me consistent results. It seems there are more options for controlling the look of the artwork in PS, and there are so many output pro- cesses for panels.

Frank Ippolito: I always prefer scanning grayscale over bitmap. the tools for refining the scan within photoshop are far more robust and offer greater flexibility and potential subtlety than those in the free scan applets.

Britt Griswold: If reproduction will be inkjet, CMYK may be best. If it will be a photoprint, RGB can work, but sRGB will be the safer color space to mach printout on screen. Work in RGB and then convert to the sRGB color space on a copy for output.

If you are going to do line art you could scan the line art at 2400dpi and overlay that in InDesign on top of 300DPI color art for the best of both.

Marjorie Leggitt: Britt and others....Below are the specs for the project I’m working on: We will output this using a six-color plotter (printing to 3M vinyl and adding a PSUV matt over-laminate). We can work with RGB or sRGB.

One question I have about your sug- gestion below is that even at 1200 dpi BW the file for just one of the images is 532MB! This is without conversion to RBG or the added color in PS. Since the scan is at quarter scale to the final output I want to make sure the line art holds well. However, if instead of importing to InDesign I decide to do the entire piece as a PS file, the thing is going to be HUGE!!! Any other sugges- tions? What is the normal procedure for doing panel size artwork in PS?

Britt Griswold: Marj, when you say “BW”, do you mean greyscale or a true black & white bitmap?

If people are going to be 3-4 ft away at the closest, you can probably get away doing 1200dpi at quarter scale in PS. If you did not have B&W ink lines you could probably do it at 600dpi.

You might look at Photoshop’s Large Document Format as the working storage file type. You might also have to work the document in strips if it is too large.

If it was me, I would scan the B&W at 1200 or higher. The[n] down-res a copy to 600dpi and keep it on a sepa- rate layer while painting your color. The[n] when done, flatten a copy of your color only (hide the B&W layer), then up res the color as needed and laying your high res B&W for the final art (in sections if needed.

Marjorie Leggitt: Yes, I did scan as grayscale at 1200dpi, not Bitmap. I like your idea of working on a down-sized version of the line art than up- resing the flattened color layer into my high res grayscale line art. Doing this I don’t think I’ll need to do in sections.

Linda Feltner: I’ve wondered. If you up-res (resample) a color layer painted in PShop, will it look like other types of art (photos or grayscale art) that sometimes just can’t handle the enlargement? or is it handled differently. Thanks in advance.

Britt Griswold: The method is the same, but the final 150dpi size is passable on things that are not hard edged like line art.

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