onnect17
Established
A place to discuss anything related to Howtek scanners.
Howtek drum scanner DIY thread: maintenance, troubleshooting, mods
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brbo
Well-known
moved from Scanview thread...
moved from Scanview thread...
THANKS!
So, after WP calibration, the scanner internally works with min. density set to the min. density of the negative which leaves more bits to the actual data range of the negative film. Makes sense now. Will try it!
Below is a link to my "raw" scan from Silverfast later, maybe you can guess from it if the results could be improved with calibration of the light path or it's just what can be expected from scanning a negative film in Silverfast (I scan 35mm negs with 4000dpi and 19 aperture). Do you have any scans available made with Silverfast?
Link to full res raw scan.
This is what I get after inverting (100% crop). If the negative is dense (like those overexposed Fuji400H), things get even worse...
(unfortunately, I don't have any sharp negative raw files at hand - this is from a plastic Instamatic lens)
moved from Scanview thread...
THANKS!
So, after WP calibration, the scanner internally works with min. density set to the min. density of the negative which leaves more bits to the actual data range of the negative film. Makes sense now. Will try it!
I think I've asked for a demo but it wasn't available (at that time). Maybe they have a demo now (for DPL 8). Problem is, DPL8 is too expensive for me. I asked Aztek if DPL7 was still available and they made me an offer on DPL 7.86 Standard, but I'm still undecided (it's still $600).
The tool is probably not widely available (and expensive), right? 😉
Below is a link to my "raw" scan from Silverfast later, maybe you can guess from it if the results could be improved with calibration of the light path or it's just what can be expected from scanning a negative film in Silverfast (I scan 35mm negs with 4000dpi and 19 aperture). Do you have any scans available made with Silverfast?
Link to full res raw scan.
This is what I get after inverting (100% crop). If the negative is dense (like those overexposed Fuji400H), things get even worse...
(unfortunately, I don't have any sharp negative raw files at hand - this is from a plastic Instamatic lens)
onnect17
Established
Ideally, you could pull-develop a roll of Ektar 100 by 1/2 stop or just cut time by 20 or 30 secs. The goal is to use a strip with min densities around 0.1 lower than the typical min densities for the C41.
It's not, actually. I will post details later. All it does is to hold a piece of 1/4" acrylic (similar to the drum thickness) in front of the focusing lens.
I have to dig for a old sample later. Not sure if I can find anything in ISO 400.
In any case you should verify the alignment of the light source, regardless of the app you using to scan, especially important with focused illuminators. Also, 19 microns is too open IMHO. It's like 1000 dpi optical.
onnect17
Established
Howtek 4000/4500 alignment tool diagram
Howtek 4000/4500 alignment tool diagram
Here's a drawing of the tool. Feel free to ask any questions.
https://1drv.ms/i/s!AugK5NQO79gPgn7NIYn5kvc12XDr
Howtek 4000/4500 alignment tool diagram
Here's a drawing of the tool. Feel free to ask any questions.
https://1drv.ms/i/s!AugK5NQO79gPgn7NIYn5kvc12XDr
brbo
Well-known
Oh, the questions will follow... 🙂
So this tool attaches to something(1) and you do the alignment of something(2) and then you observe the success of the alignment through something(3)?
Now I need a manual and start reading... Does this tool do anything else than act as a substitute for the drum, but with this tool the drum is not obstructing access to the point where you do the adjustments?
Ok, I really should start looking for and then reading the manual...
So this tool attaches to something(1) and you do the alignment of something(2) and then you observe the success of the alignment through something(3)?
Now I need a manual and start reading... Does this tool do anything else than act as a substitute for the drum, but with this tool the drum is not obstructing access to the point where you do the adjustments?
Ok, I really should start looking for and then reading the manual...
onnect17
Established
Sorry, I assumed you were familiar with the Service Manual. The alignment procedure is described in pages 6-1 to 6-3. Check the group in yahoo dealing with this scanners to download a copy. I think is named Scan-HiEnd or something like that.
The alignment is done without a drum mounted so you can access the illuminator.
meloV8
Established
brbo, quick raw invertion in silverfast hdr :
http://www.filedropper.com/h4500silverfastcolor
To me looks ok 🙂
http://www.filedropper.com/h4500silverfastcolor
To me looks ok 🙂
brbo
Well-known
Yes, Silverfast's Negafix... I don't know if I want to go there. There are times that I almost like the results, but I always come back to ColorPerfect. I can make the final results look like Silverfast (regarding noise) and still have some details in the highlights...
But still, as onnect17 pointed out, this is at 19microns. I'll try to scan some Ektar at 6 and 13microns. Last time I did that bright sky looked like my childrens' room after a week long Lego session 😉
But still, as onnect17 pointed out, this is at 19microns. I'll try to scan some Ektar at 6 and 13microns. Last time I did that bright sky looked like my childrens' room after a week long Lego session 😉
brbo
Well-known
After reading the manual about the optical alignment I don't think I need the tool to check the alignment. I'd only need it to make adjustments.
Lets hope the check reveals nicely centered light and that all that it takes is paying the Aztek price 😉
BTW, is there any point in changing the lamps even if I don't notice any streaks? I have no idea how old they are...
Lets hope the check reveals nicely centered light and that all that it takes is paying the Aztek price 😉
BTW, is there any point in changing the lamps even if I don't notice any streaks? I have no idea how old they are...
quejai
Established
I think the idea behind lamp changing is that the colour temperature / emission spectrum of the lamp could change very slightly with time, but that change might be considerable compared to the very subtle colour graduations in the film, especially negative film.
I think you should be able to get around it by using a colour calibration slide now and then, then you should be fine until it burns out.
There might be other reasons too, but I'm not sure of them.
meloV8
Established
I tried the ColorPerfect, but I could not obtain good results. I use Silverfast to reverse negative, then Lightroom for more precise work.
onnect17
Established
Remember, the purpose of the tool is not only check if the illuminator projects a centered beam. The width of the beam is also important and the acrylic in the body of the drum affect the optical path.
brbo
Well-known
Do you have any control of the width of the beam? Manual only discusses the centering of the beam.
Read some vague comments (like in this thread) that you can get by without alignment tool. Maybe I can still move the illumination lens with the drum mounted (I have one drum with heavy crazing so I'm not afraid of scratching it)? Which two screws need to be unscrewed to adjust the beam?
I also found that I'm missing the screw that's supposed to hold the FORI assembly in place.
The thing doesn't move and by the looks of it sits tight in position, but I should probably find a screw to secure the FORI. Anyone have a picture of the screw?
I played a bit with scanning with negative placed over the calibration strip. Maybe a bit better but still pretty bad. Ektar raw scan. And after inverting (with heavy noise reduction).
onnect17
Established
The width of the beam is controlled by screwing in/out the illuminator lens.
That's the tool I got. Check the yahoo forum for some pics. (hard to post them here due to size restrictions)
I still recommend you to do it without a drum. Place the scanner OFFLINE. Then select FOCUS and the option to MOVE CARRIAGE.
Half way in the arm you can find one or two allen screws that allows you to move in/out and rotate the whole illuminator head.
Some scanners came with a knurled head screw and others with an allen screw. Most likely you have the second option. Hard to see from outside.
Wait until you finish the alignment and test it again.
brbo
Well-known
Thanks! I got the drawing of the tool that you posted here and in ScanHi-End group. I'd need to investigate where I could have one made... For now, I'll have to try with the check-adjust-check-adjust method first.
brbo
Well-known
What is the optimal shape and position of the light beam (and why)?
Centered, because the center is the brightest and has least aberrations?
As narrow as possible (but still covering the largest aperture that will be used)?
If I could get the alignment tool and since you have to remove the FORI to mount it, is there any point in remounting the FORI after calibration? I don't plan to scan any reflective material. In theory, it adds (unwanted?) reflections, right? On the other hand it would leave analyser lens unshielded and somewhat exposed to mechanical damage.
Centered, because the center is the brightest and has least aberrations?
As narrow as possible (but still covering the largest aperture that will be used)?
If I could get the alignment tool and since you have to remove the FORI to mount it, is there any point in remounting the FORI after calibration? I don't plan to scan any reflective material. In theory, it adds (unwanted?) reflections, right? On the other hand it would leave analyser lens unshielded and somewhat exposed to mechanical damage.
onnect17
Established
Correct, but the procedure described in section 6.1 of the service manual is only intended to maximize the amount of light reaching the aperture wheel. It does not address the alignment of the analyzer lens to find the optical center. To do so you could use a different tool that uses a small cross-point laser, like the one in this link--> http://www.largeformatphotography.i...tek-scanners&p=1240695&viewfull=1#post1240695
The shape of the beam, as displayed in the view port, should look like the one shown in Section 6.5, page 6-7.
The FORI also acts as an aperture. So without it too much unnecessary light would get in. I taped (using black matte tape) a square aperture of approx. 1/8" in front of the FORI. Happy with the results.
brbo
Well-known
This was before adjustment:
After:
Not perfectly centered, but better than before. First test scan didn't show any massive improvement.
The light in viewport after adjusting looks like this:
Not quite centered and not really the same as manual suggests (the cener patch is too big and I don't see the second dark ring):
Hmm, getting the shape right will probably be harder than centering the light on the aperture wheel without the alignment tool...
After:
Not perfectly centered, but better than before. First test scan didn't show any massive improvement.
The light in viewport after adjusting looks like this:
Not quite centered and not really the same as manual suggests (the cener patch is too big and I don't see the second dark ring):
Hmm, getting the shape right will probably be harder than centering the light on the aperture wheel without the alignment tool...
onnect17
Established
That's was quite off at the aperture wheel. Enough to see less color aberrations in the image, assuming the analyzer lens is in proper alignment.
To reduce the width of the beam try screwing in/out the illuminator lens. Also check the spot projected by the lamp on the entrance to the fiber. Make sure is the smallest possible but still covering the 5mm fiber bundle. It may require loosing the allen screws supporting the frame of the lamp. A ND filter could help protecting your eyes here.
To reduce the width of the beam try screwing in/out the illuminator lens. Also check the spot projected by the lamp on the entrance to the fiber. Make sure is the smallest possible but still covering the 5mm fiber bundle. It may require loosing the allen screws supporting the frame of the lamp. A ND filter could help protecting your eyes here.
brbo
Well-known
Is there any way to adjust the analyser lens? Can't see it mentioned in the manual.
If I get good centering on the aperture wheel but off-centered image in viewport this could also be because of flip-up mirror? This is non-issue, but if the cause is in the analyser lens misalignment...
Could you explain how to check if the analyser lens is positioned correctly? Unfortunately, I don't understand how one would use the cross-point laser for that. Thanks!
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