jzagaja
Well-known
Benefit is you can produce less noise in blue channel and less heat, no need to change bulbs, ready to use in seconds. Of course HLX halogen is cheap today about 4-5 eur. Also it's good to have such a bulb cor slide projection, telecine and movies.
brbo
Well-known
Any plans for making the thing as plug&play as possible and selling to Howtek owners? I'd be very interested. I'd expect less noise would be most beneficial when scanning negative film (especially when scanning with software that is not DPL)?!
monkeyfist
Established
With RGB leds you could also adjust the color of the light similarly as you do in color enlargers. Eliminating the mask of colornegative.
One problem i also have, is when scanning large files in multiple parts. The light intensity can change.. as the lamp heats ups or cools down. With leds this might not be the case.
It would be probably pretty easy to put together, using arduino as controller:
https://www.youtube.com/watch?v=5uzydVKoZtM
I also think that LEDs do not produce IR or UV light, so the whole filter would be unnecessary. At least i can use my LF scan back without UV/IR filter if i use LED lightsource.
Im pretty sure somewhere out there is a ready made solution, as these things are pretty common:
http://www.ebay.com/itm/Outdoor-IP6...-LED-Floodlight-10W-20W-30W-50W-/290763685703
They have a pretty rudimentary light color controller, would only need to have more accurate controller.
onnect17
Established
DPL can not resolve the issue with the Howteks light source begin insufficient. Only extra light reaching the PMTs (or/and more sensitive PMTs) can reduce the noise in the high densities. What the log mode available in DPL can do is reduce the degree of correction needed while scanning negatives, and so the amount of artifacts produced as a result.
I am not interested in selling the lamp at this point. I rather share what I am doing and get other owners involved. That's the goal. I will take a few pictures next time I assemble one and I am sure others in the forum can make it better. And it's pretty cheap. The cost for the parts is only around $10. If your guys can locate an Scanview owner near the Boston area I do not mind stopping by and get some measurements.
The current design for the Howteks is as plug and play as you can imagine. All you need is to remove the current lamp with the base, loose the fiber optic using the allen key, place the led lamp in front, tight the fiber optic and attach a elastic band. Less than a minute to install it.
onnect17
Established
As you said, leds could help to compensate for the c41 mask. From the practical point of view, depends on the scanner model. In the case of the Howteks, I rather place a emulsion sample in the calibration area. That will take care of it.
Regarding light source stability, in the Howteks the calibration routine set the white point before the start of each scan and correct it in each raster line to compensate for any light source drift. To my knowledge, no such mechanism is present in the scanviews so I think drift (as you mentioned) is an issue here.
The leds output are also sensitive to changes in temperature. The difference is they are a lot easy to control. In the case of the prototype, includes a fan which only purpose is to keep the temperature steady. But I don't think that even any logic is needed. If so, a simple thermistor in the path of the fan would do the trick.
monkeyfist
Established
In scanmates you can also do a white calibration on the negative mask, it will do the trick of eliminating the mask.. but it adjusts gains by software. So i assume the best results could be achieved with changing the color of the light.
Maybe not too important, but might be fun to experiment.
And sure, leds need cooling.. they get really hot.
I found this arduino shield:
http://www.ebay.com/itm/Arduino-Hig...12bit-channel-dimming-3-x-700mA-/181386751572
With this, i could control a 30w RGB led with 12bit accuracy. I assume i need at least that to get near the light output of the 75w halogen.
onnect17
Established
I do not think this board in particular is appropriate because it uses PWM to control the output. That will show in the scanned images as a flicker.
monkeyfist
Established
I think it does both, analog & PWM.
"Dynamically adjustable constant current 100mA - 700mA per channel allowing for analog dimming."
onnect17
Established
It's just wording. Limiting the output current does not change the output waveform (still square). Also, the switching PS stage at the end will add some extra ripple but a good capacitor could take care of that.
Still a good shield for many other projects.
Netsoft2k
Well-known
Does anyone know how to apply the gamma setting in Color Quartet that is so easily available in Color Trio? I am asking because I am noticing that I get much better shadow detail for under-exposed velvia and provia if I set the gamma value higher.
Unfortunately, I can't seem to find a way to do this in Color Quartet and would appreciate any help.
Thanks!
Pali
EDIT: Nevermind. This was a user error and not an issue with Color Quartet. Saving in RAW and applying the Gamma in Photoshop does what I need and I don't see any loss of shadow detail between CQ and Color Trio.
Unfortunately, I can't seem to find a way to do this in Color Quartet and would appreciate any help.
Thanks!
Pali
EDIT: Nevermind. This was a user error and not an issue with Color Quartet. Saving in RAW and applying the Gamma in Photoshop does what I need and I don't see any loss of shadow detail between CQ and Color Trio.
monkeyfist
Established
"Programmable constant current switching frequency from 330KHz - 1MHz."
Doesnt this mean, the led blinks at 1Mhz rate? isn't it a bit too fast for the scanner to pick up? I think you are overthinking here. Isn't the halogen bulb also basically blinking?
onnect17
Established
And the A/D converters are pretty fast too. You will be able to see the jitter in you images. Any ripple in the output bigger that one bit will impact the quality from the get-go.
The halogen bulbs are pretty slow, which is helping in this case. It's not the case with leds. Some can switch pretty fast. Besides, I am sure the lamps in the scanmates are getting a nice and clean DC feed.
Adam Long
Newbie
Pali, many thanks for the guide. I've bought the new filters and am planning to give this a go on my SM5000. I don't shoot much neg but excessive red in the shadows has been a problem with my scans, especially on Velvia 100.
I've not done the PMT adjustment before, so can you give me an idea of what the mistake was so I can be sure to avoid it?
Many thanks, Adam.
Netsoft2k
Well-known
Adam,
Good luck with the process. I had plugged the white cable at connection 19 [ABCDEFGHI] out of alignment skipping one pin at the end. This is where I believe the power comes to the board and that's why I caused some damage.
Be careful and you'll find its a straight forward process.
Regards,
Pali
Netsoft2k
Well-known
I bought a backup scanner which I will be leaving in storage and wanted to ask if I should store the scanner with the extra drum mounted or off? I usually leave the drum mounted in my primary scanners but I don't know if leaving them on the scanner is a good idea for long-term storage.
Adam Long
Newbie
Thanks Pali,
Reading the service manual, it suggests you need the extension unit for the mainboard. I don't have one. Looking at your photos, it looks like you managed without?
Adam
Reading the service manual, it suggests you need the extension unit for the mainboard. I don't have one. Looking at your photos, it looks like you managed without?
Adam
Netsoft2k
Well-known
Hi Adam,
Yes, its possible without it but you'll need to figure out what is the easiest way for you to reach the test points on the board. As you can see in my pictures, I connected the test points using thin wires that had I had bent into a "U" shape and held in place with slight tension. Notice the tape that is holding the wires in place during the test.
The extension board will make your access to the test points much easier but that's all it really does.
Pali
Yes, its possible without it but you'll need to figure out what is the easiest way for you to reach the test points on the board. As you can see in my pictures, I connected the test points using thin wires that had I had bent into a "U" shape and held in place with slight tension. Notice the tape that is holding the wires in place during the test.
The extension board will make your access to the test points much easier but that's all it really does.
Pali
brbo
Well-known
I hope it's OK to also ask/post some Howtek related stuff in this thread...
Is there any benefit in canceling C-41 mask at calibration vs. later in software? How do you mount your film on the drum so that your calibration strip is covered with blank film?
Maybe I've asked this before, have you done (or know of) any comparison of negative scans between DPL (in log mode) and other software (I have Silverfast)? I'd like to get an idea of what to expect from DPL.
Also, how much work does it take to check the optical path alignment in 4500? Any special tools required?
Thanks!
Is there any benefit in canceling C-41 mask at calibration vs. later in software? How do you mount your film on the drum so that your calibration strip is covered with blank film?
Maybe I've asked this before, have you done (or know of) any comparison of negative scans between DPL (in log mode) and other software (I have Silverfast)? I'd like to get an idea of what to expect from DPL.
Also, how much work does it take to check the optical path alignment in 4500? Any special tools required?
Thanks!
Kamph
Established
Lately I've been scanning a ton of film on my Scanmate and become a lot more familiar with both the scanner and ColorQuartet and now find it increasingly hard to use any of my other scanners. I do, however, have some of that "zipper effect" which was mentioned earlier in this thread. Is it an encoder or motor issue?
Also I spoke to Micheal about the whole 16bit problem, and they seem to be aware of it. I hardly ever shoot anything but negative film, so the lack of the 16 (or rather 12bit) option is a bit of a let down - I do hope a solution will be found at some point.
I would love to be able to wet mount as well, but it's almost impossible to get hold of a mounting station. TBH if it weren't for the newton rings dry scanning would be more than tolerable - I dont seem to get out of focus parts on the scans anymore after I learned to mount properly.
Also I spoke to Micheal about the whole 16bit problem, and they seem to be aware of it. I hardly ever shoot anything but negative film, so the lack of the 16 (or rather 12bit) option is a bit of a let down - I do hope a solution will be found at some point.
I would love to be able to wet mount as well, but it's almost impossible to get hold of a mounting station. TBH if it weren't for the newton rings dry scanning would be more than tolerable - I dont seem to get out of focus parts on the scans anymore after I learned to mount properly.
Kamph
Established
I can't speak to the Howtek, but I tried to calibrate on the negative mask on my SM5000 and it resulted in an error.