The Artec A6000C-M Scanner

Some pictures on my Web pages were scanned using the Artec A6000C-M Scanner from Ultima International (Macintosh version). My experience with that scanner has been interesting, to put it mildly, so I thought I'd write down some observations here in case anybody out there is thinking about buying one.

Before I continue, I should say that I don't have the Artec scanner anymore. It worked fine for a few weeks, but a couple of days ago my system froze up hard while I was doing a scan. The crash was so bad it wiped out my Mac's System file. After many hours resurrecting my Mac, I tried the scanner again and it didn't work. The scanner is at this moment winging its way back to the dealer. I don't really know if the scanner's design or manufacture were at fault, but I'll be using a different brand from now on!

I had seen comments elsewhere on the Web that the Artec is a good greyscale scanner, but that color images don't look right without a lot of fiddling. I was disappointed myself at first by the difficulty of getting decent color, and especially getting adequate tonal range. But I learned a couple of tricks that helped me get useful images without much trouble.

The bottom line on the Artec scanner is that when it works, it works OK--for my purposes, at least. I don't have experience with high-end scanners, but even without that bias there are a couple of things I'd really look for in a better scanner:

• First, I want scanner settings that let me select the brightest and darkest value on an image before it is scanned. The Artec setup assumes every picture has ideal color range from bright-white to black. You can adjust the image in Photoshop, but only by throwing away some of the image's color range. This drawback is inevitable for any post-scan levels adjustment.

  You might think 16 million colors is enough that you can toss a few out, but you really only get 256 distinct shades of any hue, and the image of a particular object might have to be shaded using only a few colors. So, for example, the smooth, contoured power bulge on your red car's hood might wind up looking like an inverted pie tin if you lose too much color resolution.

• Second, I'd like a scanner with more internal color resolution. It is true that most image files can't handle more than a 16 million color range, but that really isn't enough to start with. The computer plays tricks to make 16 million, or thousands, or even just 256 colors look nearly as good as a photograph, but to do that reliably it has to start with a higher color resolution. Even at 16 million colors, it is possible for shaded contours to look banded if the scanner doesn't start with at least a little more resolution.

[So how did the OneScanner work out?]

Artec Tricks

First, ignore the "Ready to Scan!" message the first time it comes up on that cute LCD display. I nearly went mad trying to achieve good color balance at first. Then, on a whim I guess, I turned the scanner off and on again after I had been fighting color balance for a few hours. The scanner's power-on-self-test (POST) calibrations were suddenly dead-on and I was getting decent color (still dark, though) without much tweaking at all. For the most part, I gave up adjusting individual color levels. The moral: Give the lamp plenty of time to warm up (maybe an hour or so), then shut down and restart the scanner so it can do its POST calibrations again with a warm lamp.

Second, forget the Artec's Gamma setting. For all intents and purposes, I think you might as well assume the Artec has no calibration settings at all. Aside from being difficult to use (you can't see what effect your changes have until after you scan) they don't appear to affect the scanning levels at all. Instead, they appear to be a post-acquisition filter of the scanned image--and a poor one at that. This is just my impression, but it's the only explanation I can think of for the poor results I got when using the Artec settings.

You do need a gamma setting, but Photoshop LE (included with the Artec version I purchased) has an excellent one, in a dialog called "Levels." I couldn't make much sense of the LE manual's explanation of how to use it at first, and there are still parts that make no sense at all to me (at least for color images), but the parts I've figured out work wonderfully. Photoshop LE also includes a calibration procedure and gamma setting for your monitor (in the Goodies folder), but I never had a chance to try it.

Here's what I wound up doing to get decent scans:

1. Take an 11-step gray wedge (mine was a bar with 11 swatches: white on one end, black on the other, 50% gray in the very middle), and scan it in RGB. I created my wedge by printing it on a black and white printer, so I gave the scanned image a generous blur to wipe out the halftoning pattern. (Not ideal, but the camera stores were closed.) You'll use the wedge to find a quick, almost automatic setting that'll make most of your scans look good.

2. Open up Window->Palettes->Info and then Image->Adjust->Levels in Photoshop. That graph in the Levels dialog is a histogram of the image. This is just a bar graph showing, left to right, a count of pixels for each shade from darkest to brightest. Grab the grey pointer under the middle of the graph and slide it to the left. The image's midtones get brighter. That's gamma.

3. Point the mouse at the 50% swatch on the gray wedge and look at the Info palette. If your wedge is uckey like mine, you might have to wave the mouse around to get an idea of the average shade. Keep twiddling the gamma until the 50% swatch's RGB values are all about 128 in the Info palette. The middle readout on the histogram shows the gamma you've set. Mine settled in at 1.98.

   You might also want to switch from the RGB graph to Red, Green, or Blue, and twiddle those to tweak color balance. I didn't feel like it was possible, or even worth the trouble, to get all the numbers dead-on, at least not without a proper wedge. When you are done, Save Levels.

   (I tried using Artec's control dialog to enter the "ideal" settings I'd come up with in Photoshop. The results were nothing like the same. That's when I gave up on Artec's settings.)

4. Now scan an image. For computer display, I usually scan at 300dpi unless its a small image, say walletsize, which I'll scan at 600. That's a lot more resolution than you'll need or want in your final image, but I do this for a reason, so be patient.

   (I admit it helps to have a lot of memory and disk space. I gave Photoshop 15MB RAM and 100MB scratch space, and it was still pretty slow on my little Performa 476.)

5. My images consistently come out dark at first, but after that rigamarole with the wedge, they are easy to fix. Open up Levels and load the levels you saved a couple of steps ago. Bang. The image already looks a lot better.

6. Look at the histogram. Most photograph histograms I've seen have "hills" at the left (dark) side and a slope leading down to the right (bright) side. Often, the slope bottoms out before it gets all the way over to the right, and the rest of the graph is blank. This either means the photo itself is a little dark, or just that the paper is darker than the reference white card that's built into the scanner for its POST calibration.

7. If your histogram's hill doesn't reach all the way to the right, grab the right-hand (highlights) pointer under the histogram and slide it over to the base of the hill. Bang. Your whites are now bright and the image is even prettier.

   Sometimes you will see a lone hillock 'way over at the right. That represents some unusually bright pixels in the image: a tear in the paper, a lamp in the field of view, an overlit foreground object, or even just a white border. I usually slide the highlights pointer right past such an anomaly. This washes out part of the image, but usually not a part that I care about.

   Also, sometimes the slope tails out into a long plain just one or two pixels high. I'm not sure what this is, but I usually wipe that out, too. I like the results.

8. For 95% of the images I've scanned in the last few weeks, this is all the levels adjustment that was needed. I'll let you figure out all the other Levels settings yourself! Close the Levels dialog when you are satisfied.

   If you want to learn something, open Levels up again. Hey, what happened to the histogram? It was a densely-packed bar graph, now it probably looks like a comb--with blank spaces between the colors. Adjusting the levels spreads the existing colors out to fill the "color space" differently. This can "posterize" parts of the image so that colors look banded instead of smoothly shaded.

   This loss of color resolution is the biggest disadvantage to setting levels after the scan, and not before. It is why I scan at considerably higher resolutions than I actually need. When I reduce the image size after setting levels, Photoshop averages the extra pixels before discarding them, effectively trading in excess spatial resolution to regain some of the lost color resolution. If you look at the histogram again after resizing, you'll see that it's smooth again.

9. If your image needs cropping and you want it to be a specific size when you are done, crop it now, before resizing it.

10. Also, if you need to do any touch-up work, now is a good time. The Airbrush tool is really cool, isn't it? Even at this resolution it's pretty fast, and you can zoom in close so that minor imperfections in your airbrush work will go away when you make the image smaller.

11. OK, now for the final touch. Select Image->Image size... and select the size you want for your final image.

    I've settled on making the larger dimension 1024 pixels most of the time. This gives me an image that I can zoom into some for details, but that's usually well under 100K on disk if I use Low quality JPEG compression, and not far over 100K at High quality. Of course, I make Web images much smaller (no more than 300 pixels across) to reduce transmission time.

    I always set the resolution to 72 dpi for screen display.

One final note, make sure there's plenty of difference between your scanned image size and your resized image. I noticed that if there wasn't enough difference, the resized image sometimes had banding and patterning artifacts (technically this is called "aliasing," almost but not quite the same as the aliasing that causes jaggies). If you must scan at a resolution near your final output, I recommend not resizing at all, or at least saving before you do so you can revert if it looks awful!

So that's my recipe. Season to taste!

Le Mort d'Artec

I don't know if my particular scanner's failure should be taken to reflect on the Artec brand, but it was certainly a hardware problem. After the crash, I wiped out my 7.5.3 MacOS System folder (which was misbehaving itself anyway) and rolled back to the familiar 7.5. Then I did extensive diagnostic tests, especially of my SCSI bus (for example, overnight looped tests of hard drives on both ends of the SCSI chain, with the sanner in-between). Everything passed with flying colors. I even checked the scanner's fuse for continuity (the manual's only real troubleshooting tip) and it was fine, too.

The failure mode was interesting. I would go to start a scan in Photoshop (select Acquire->Artec Scanner), and then select Preview in the scanner control window. The scanner light would turn off (!) and the carriage would start moving. Then everything would stop and a message would be displayed saying there was an error sending the command to the scanner. When I dismissed the window, the carriage returned to its home position and the light went back on. In WordLinx (OCR), the behavior was the same except the light never went off.

It hadn't been 30 days since I ordered the scanner from MacWarehouse (long may they wave), so I called their service department and was transferred to a tech. He was very helpful and suggested I try a couple of other things that didn't work either. Then he gave me an RMA number, an Airborne account number, and a number to call for pickup. The scanner was on its way back to MacWarehouse a few hours later--on a Saturday! Now that's service.

We asked MacWarehouse not to send us another scanner. I was pretty satisfied with the Artec before it bombed, but my wife fell in love with Apple's new Color OneScanner 600/27 right after we received the Artec. Maybe it was lucky that the Artec died. We were certainly lucky it didn't die a few days later!

[So how did the OneScanner work out?]