Second try on this...had a reply all set to post and it disappeared...I'll try not to lose this one!
Thank you all for the (indeed) sage advice. I will put off the thoughts of a K-3 for the moment and concentrate on finding better lenses. I will try and address the points y'all brought up. First, I have a great tripod setup that I am using, and I am also using the "2-second delay" to lock up the mirror for each shot, so those are taken care of.
The lights are, indeed, less than optimal...I'm using the set that has two heads on the adjustable stand, 500 watt bulbs in each head. I aim one head up to bounce off the ceiling, and the other down to bounce off a white surface. I need to find better surfaces to use to bounce them off of...I've been using pieces of that white "dry erase marker board" (what we've always called "Teacher Board") to bounce the light. And I have found that the K-30 usually gets the "white point" within 100-200 degrees either side of 3200, and I have been setting the white point to 3200 when I open the RAW files. I will also look at getting different lights, as these halogens get extremely hot, and pull a LOT of juice. As it is, I've re-adjusted the lights for each different piece, one bounced 'above" and the other bounced "below" the image, so that the piece is lit only by as indirect a light as I can get. The halogens seem consistently to be around 3200 for a temperature, but I will check out other lights.
As far as what the art is: Mainly paintings, but also drawings, sketches, collages, etc...they range in size from very small (just a few inches square) to several feet on each side...up to 3 ft x 4ft. There is also some "3D" art (assemblages, small covered boxes/tins, etc) that I will also photograph. At the moment, I am working on the paintings and other flat work. The paintings are mostly acrylic, some oils. The most time so far has been spent adjusting the "bounce" of the lights so that they do not produce a glare on the paint surface itself. She used a semi-gloss medium a lot of the time, so the glare of the light is a problem, and even "bouncing" sometimes does not kill it 100%.
So far, the way I've been working is to take 20 or so shots of each piece, noting where the lights were, how far away from the wall the tripod was, etc., and then going through and finding the ones that look the most "correct" to my eye. I will look at the information data to see what focal lengths have given the best results. I have found that the closer I can put the tripod to the wall (the more "zoomed out" the 18-135 is) the better things tend to look. When I've opened the RAW files with Photoshop (CS5) I was glad to see they had a "lens correction" setting that gets rid of the "pinched in" sides that the zoom was giving. If I can avoid that with a better lens, then that would be great.
Working this way, it took me from 10:30 am until about 5 pm yesterday to get the two shots I was thinking were "ok"...not GREAT, but "ok". I saved them as large (20 MB or so) PNG files and upped them to my webspace to show what I've been able to get using what I have to work with. I will leave these up for a few days, and then remove them.
This first piece is an early self-portrait she painted in the middle-1970s, with very much "70s colors" (earth tones, yellows, browns). The color on this particular shot was as close to the real thing as I could get, only made a few small adjustments to the RAW file. This painting measures 28" x 36":
http://www.beebstuff.net/misc/IMGP0441.png The second shot is from a series of about twenty tree paintings she worked on from the mid 90s until about eight years ago, with mostly blues and aquas...I'm not as happy with the colors on this as I was the self-portrait. This painting measures 30" x 24", or 37" x 32" with the frame:
http://www.beebstuff.net/misc/IMGP0444.png These are both 20 MB or more files, so they might take awhile to download.
Ideally, I'd like to be able to make full-size prints from whatever files I end up having. A friend suggested that if the K-30 couldn't give me sharp enough images to work with, that a software called "PhotoZoom Pro" might be worth looking into. But before that, I'm going to take my K-30 into Precision Camera and see if they will let me try out some good prime lenses there in the store, so I can see what would be getting. I'm betting that a 70mm might be optimal, but I will look at every one they have that will fit. The only other lens I have is my original ancient 50mm that came on my K-1000 way back when, which I haven't tried to use with the K-30 yet...I'll do a search here and see what I have to do to use it with my K-30. I would imagine somebody has come up with a way to use the old Pentax glass with these new-fangled cameras
I will check out what prime lenses they have in stock and see what I can come up with.
Again, many, many thanks to all...I will report back when I have some better glass!