question about using the 4x5 Epson scanner lens to scan 5.9" wide and stitch 8x10

[Pere Casals]

Contrast Adaptive Sharpening (CAS)

Adaptive Sharpening with Overshoot Control.



Additionally I would like to remark that the digital optimization work many Pro scanners do is completely evident.

If we see the Howtek crop from the Collaborative Scanner Comparison it is clear that the edges have a deep digital work. If one often takes a microscope to inspect film those edges are from another planet, they are not natural to the lens-film work. Those scanned/enlarged edges are impossible with that low contrast.


If we inspect film with the microscope what we see (at that enlargement) is Epson look.

I theory "internal sharpening" is intended to correct the system pitfalls, not the taken image, as the taken image should be corrected in another level, but in certain conditions it would be difficult for the internal sharpening to guess if blur comes from the taking lens or from the scanning system.


What it's absolutely clear to me (from next crop) is that the howtek did a deep digital optimization work in those (another planet) edges that had to be blurred in the negative, for this reason the (rawer) Epson image can be matched to the Howtek one with Ps:







IMHO the reason why the Epson matches a fancy Howtek is simply because that LF negative has not much more than the Epson can take, and if the Howtek showed those alien edges it is because the edges were blurred on film and the internal digital sharpening did a job, while in the Epson case that job has to be done in Ps.

[Michael Roberts]

To me the area guide allows perfect 2m prints, you always can wet mount on bed glass

Upgrade to V800, sell the 4990 for some $150. The V800 has LED illumination so there is no heating time delay for pre-scanning.

Pere,
A couple of follow up questions for you:

1. Others (e.g., Sandy King, Ben Horne) have commented the sharpest focus for the lens with Film Area Guide (i.e., the 8x10 lens) is 1mm above the glass. Have you tested this? In your experience is performance "good enough" with dry or wet mounting directly on the lower scanner glass? I am thinking about buying the Aztek kit and just mounting 8x10 directly on the lower scanner glass....but if I need to raise the film 1mm, then I need to figure out how to do that also.

2. Is there any other advantage to the 800 over my current 4990 if I'm just going to fluid mount directly on the scanner glass? My understanding is the resolution for the 8x10 lens (with Film Area Guide) is the same for the 4990 as for the 7xx/8xx series of scanners. Seems like I may as well keep the scanner I have than trade up unless there is some other advantage--unless the cooler leds make a big difference.

Thanks!
Michael

[Sasquatchian]

Those test scans were done many many years ago by operators who had no idea how to properly use the software. That was clearly evident in the comparison between Aztek's version of the same HR8000 Howtek where the maximum resolution was wildly different (lower) with the identical Howtek. Well, it turns out that Colorbyte designed the "auto" aperture feature of the software to NOT choose the 3 micron aperture when selecting 8000 ppi. That was because so often, that would result in grainier, noisier scans when the film itself didn't support that res. I'm the person who discovered that and that you have to manually set the aperture if you want that minimum aperture. All that is to illustrate the the scanner operator makes a huge difference and if you don't understand the software, you get skewed results. Since the default behavior of Trident IS to provide a certain amount of sharpening, that is most likely what you're looking at in the Howtek scans. The Trident sharpening module is very interesting when you get into it and it was genius for prepress purposes but has no place in fine art RGB scans. There is absolutely no hardware sharpening going on in the Howtek drum scanners. I've been through that for the last twenty years when I spent more of my time conversing with ColorByte about how their software worked. I'm going to go out on a very short limb and say that those scanner tests are flawed and unless I could see screenshots of all the windows in Trident, I'll stick by that opinion. Another thing that makes a big difference on these scanners is whether the optical system on the scanner has been manually custom aligned. The early off the shelf Howteks were more likely to not be perfectly aligned compared to the same machine sold by Aztek where that was one of the pre-sale operations done before delivery. Having compared the hi-res scans from my own HR8000 with the optical alignment done, those scans are better than any other scanner I've seen except perhaps the ICG's, which, of course, have no support left.

[Pere Casals]

1. Others (e.g., Sandy King, Ben Horne) have commented the sharpest focus for the lens with Film Area Guide (i.e., the 8x10 lens) is 1mm above the glass. Have you tested this? In your experience is performance "good enough" with dry or wet mounting directly on the lower scanner glass? I am thinking about buying the Aztek kit and just mounting 8x10 directly on the lower scanner glass....but if I need to raise the film 1mm, then I need to figure out how to do that also.

That bell was scanned directly on glass https://www.flickr.com/photos/125592...5/32535835184/ with emulsion down to avoid NRs

The Low Res lens is also used to scan opaques, so it has no sense to focus 1mm higher as the opaque is pressed aganist glass. I tested performance with the glass slide directly on glass to check if gear was ok but I've not tested 1mm. Nor Sandy King or Ben Horne would be jocking about that, so it would be worth to investigate it.

The LR lens should have some greater DOF than the HR lens, probably there are assembly tolerances and perhaps focus is placed in a way that it ensures a good performance, and perhaps there is some variability in different units. I'll check it next time I scan.

Without a USAF 1951 glass slide, there is a very easy way to check what is perfect focus distance:

https://jrileystewart.com/blog/2017/...atbed-scanner/
https://web.archive.org/web/20190701...atbed-scanner/

2. Is there any other advantage to the 800 over my current 4990 if I'm just going to fluid mount directly on the scanner glass? My understanding is the resolution for the 8x10 lens (with Film Area Guide) is the same for the 4990 as for the 7xx/8xx series of scanners. Seems like I may as well keep the scanner I have than trade up unless there is some other advantage--unless the cooler leds make a big difference.

I've never tested the 4990, tests around indicate that the 4990 performs like the V850 with the Low Res lens, so my guess is that you won't notice much improvement for 8x10, but some report an slight improvement.

https://www.flickr.com/photos/mikeco...7594426285173/

Here they find that the drum at 3300 is slightly better than the 4990 at nomial 4800
https://web.archive.org/web/20171203...tbed-scanners/

And what I find is that by editing that crop in Ps I equal the drum result, in two or three clicks




Anyway the V800 has no heating delay, this is very convenient!

[Pere Casals]

There is absolutely no hardware sharpening going on in the Howtek drum scanners. I've been through that for the last twenty years when I spent more of my time conversing with ColorByte about how their software worked

This does not happen in software, but in firmware.

[Michael Roberts]

Pere, thank you so much!

[Jim Andrada]

Hi Michael. I thought I had responded to your question of how to mount 4 x 10 on the Epson but it doesn't show u here, so here goes again

Just wet mount the 4 x 10 on the carrier glass (the glass carrier that's part of what they call the mounting station)

This thread seems to have gone off the rails a bit into the tech weeds - I think you were asking a pretty simple straightforward question.

I solved the question by getting a bigger scanner with focusing ability. I haven't used a larger Epson but...

[Sasquatchian]

Pere - How would you know, looking at those scans, whether something happened in software or firmware? Do you own a Howtek? Have you ever operated one? I have never seen anything that looked like anything other than film grain from the high res scans, either 4000 or 8000 ppi from either of the Howtek's I've owned. Now it is true that certain Hell Chromagraph scanners did do what you claim and even Imacon Flextight's sharpened the image somewhat when the USM was set to zero, but what evidence do you have that Howtek did anything like this in firmware? I'm not buying what you're saying without definitive proof.

[interneg]

Now it is true that certain Hell Chromagraph scanners did do what you claim and even Imacon Flextight's sharpened the image somewhat when the USM was set to zero, but what evidence do you have that Howtek did anything like this in firmware? I'm not buying what you're saying without definitive proof.

And it is important to note that most of these USM's can be bypassed or turned off - because it's usually just in the scanner software. The infamous -120 USM setting for the Imacon in TIFF mode switches off the USM - confusingly, in the 3F mode, 0 in the USM apparently equates to the same thing... I long ago ceased wondering about the eccentricity of high end scanner software.

Firmware sharpening suggests it has to happen inside the scanner before it even reaches the computer - and these sort of claims need exceptional evidence - which you won't find forthcoming because Pere has never operated or owned a Howtek/ Aztek, let alone looked inside one, or gone through the software as comprehensively as you have. He seems to believe he's one sharpening routine away from turning a V700 into a high end scanner...

[Pere Casals]

He seems to believe he's one sharpening routine away from turning a V700 into a high end scanner...

LOL

Personal attack is your single resource.

V700 is not Pro gear, but it resolves 2900" x 5.9" = 17110 effective pixels in the scan width, no crappy lenses and folded optics inside. Your X1 resolves 1/3 of that.

While the X1 is stellar for 35mm rolls it's beaten by the cheapo V700 in LF, sorry, but your personal attacks won't change that. The X1 has a painful shorcomming: a sensor with only 8k, and no way to displace it to take crops that can be stitched.