Make sure that the lead from the back of the lid is plugged into the socket in the scanner body.
Indeed!!! You are a gentleman and a scholar!
My 4990 had to be repaired many years ago, and I disassembled it in order to put it back in the original carton (which I still had at that time) so that I could safely bring it to the Epson repair center. And then when it was returned after repair (again, they put it back in the carton) I reassembled it once it was back on my desk. And apparently I never reconnected that cable in the rear of the lid to the socket in the rear of the base. And it never mattered since I was only doing "reflective" scanning and also had the white document mat inserted into its locks.
But obviously it needs to be connected in order to then shine light through the transparencies (aka "35mm slides"), for the scanning method I'm now wanting to do. And of course once I connected the cable that mechanical prerequisite was satisfied.
However what I still didn't realize (and which really was my major mistake of misunderstanding) was that it was the FIRST BUTTON in Silverfast which needed to be toggled between "Reflective" and "Transparency". I had foolishly assumed it was the SECOND BUTTON ("Positive") which needed to be used to specify "Kodachrome" (since after all, the cardboard mounts around each 35mm slide say "Kodachrome"!), and yet the "Kodachrome" value in the dropdown list from "Positive" is still grayed-out and unselectable. I don't know what might really be meant by "Positive" or what "Kodachrome" might correspond to (perhaps film strips? not slides?)., but it's obviously not relevant to my current objective of scanning the 35mm slides dropped into the 8X holder.
==> It is REFLECTIVE changed to TRANSPARENCY that is really what I want.
I also upped the scan resolution to 2400 ppi, and pushed "Prescan".
Then, I discovered also had to make some Preferences changes (which I learned from some online video and also a prompt from Silverfast):
(a) Edit -> Preferences -> General -> High-resolution prescan -> 2X, which facilitates "finding frames" more accurately (after prescan) for all the slides placed in my 8X tray
(b) Edit -> Preferences -> Auto -> Find Frames: Outset -> 5%, which adds a bit of "extra outside pixel padding" around the frames found by IFF, just to ensure no unwanted cropping or trimming. This excess can be cropped away during post-scan editing (say with Photoshop) if desired, or it can just be retained as a perfectly acceptable small outside black border area around each true image.
So once the high-resolution prescan had completed, I could then push the FRAME button and select Find Frames -> All frames. Amazingly, it worked perfectly, with an outline placed just outside (with 5% "overscan") the transparency inside each cardboard mount. Remarkable!
And then I discovered that there is a "Batch Scan" button which does EXACTLY what I'd hoped I would find, namely performing 8 scans automatically when I pushed it, moving through all 8 of the 35mm slides in the tray and creating 8 individually named TIF files. PERFECT!! Of course I can also still do just one at a time with "Scan" if I want.
I then used Photoshop to rotate each image if necessary. Most were "upside down" (because of how I placed the slides into each window of the tray) and in need of a 1280 detree rotation, and some were in need of a 90 degree rotation. Now that I understand that as I move through the rest of the 500 slides I will inspect each one before putting it into the tray, which will save Photoshop time at the other end of the scan.
And now for the moment of truth: the level of detail in these resulting TIF files was truly remarkable. I would not have imagined it could be so good. Sure, if the image inside the slide is not perfectly in focus or highly detailed then the scan of that image will not be perfectly in focus or detailed. But it is astonishing how this scan of such a small piece of positive film transparency can be so good. And also that the "focus" of the camera lens under the scanning glass is so sharp by default, seemingly perfectly matched for the thickness of the cardboard mount around each slide. Honestly, amazing.
Finally, I played around with comparing scan results at 2400 ppi vs. 4800 ppi. Using Photoshop I then resized each image to 1920 pixels wide (producing about 1320 pixels tall), both retaining the original 4800 or 2400 ppi resolution, as well as scanning at 4800 and then reducing it to 2400 during the image resize. And I also saved to both TIF, JPG and PNG, to compare the detail and color of each resize/compress. My feeling is that scanning at 4800 ppi generates much too much data and produces "blurring" during the resizing. The final resized images from 2400 ppi scans were much "clearer".
Also, it seems that the JPG resize/compresses had pretty much the identical color as the original TIF scan. The PNG resize/compresses were just slightly off, or at least just a tiny bit different... and I noticed it.
==> For the goal of this project I will scan at 2400 ppi, and then use Photoshop to resize each scanned TIF image to 1920 x 1320 and save to JPG with a quality of 11. Note that Photoshop has its own File -> Scripts -> Image processor, that allows automated resize/compress of many TIF files into JPG. So once I scan all 500 slides, the conversion to JPG will also be effectively done by a single button push.
Given that these are 35mm slides from 50 years ago I think the display JPG results of the first eight slides that I have now experimented with are superb!!! Just superb!!
So once again, thank you very much for telling me about that cable. But my real mistake was that I thought it was through the "Positive" button from which should then select Kodachrome (and which for some reason is grayed out), when in fact I really should have pushed the "Reflective" button all along, and then selected "Transparency". I've now done that, and case closed!!
