Silverfast Ai demo for Howtek, am I supposed to choose HDR and turn off EVERYTHING else?
Silverfast Ai demo for Howtek, am I supposed to choose HDR and turn off EVERYTHING else?
Yes, and HDR gives no access to other controls anyway, so by nature they are "off". The only thing you need do to make sure you are getting no alteration of the data is to uncheck the box for applying gamma setting to HDR, and turn off color management.
Also, this varied use of the term "Raw" is muddying the waters... I hope you know what I mean.
Tyler
Thanks!Originally Posted by Tyler Boley
One more question regarding this method... What color space is this *RAW* thing? and how am I gonna convert it into some Adobe or prophoto RGB space in photoshop without color distortion? Does Howtek has no internal color space reference, and simply mapping all it sees into 0~4095 (12bits) values without any color reference?
btw, what software do you use to convert this TIFF raw into useable gamma 2.2 RGB files?
it's not RAW in contemporary nomenclature, which is now a file format associated with digital capture. It's raw in the sense that it hasn't been "cooked". It's a description, not a particular type of file.
It's just a normal tiff, but has not had any processing done to it. Vuescan has that option also, I don't recall what they call it.
Unless you create a profile for that particular set of HDR settings that created your file, it is associated with not particular color space at all, it must be assigned something. Assigning changes nothing, so you need not be concerned with any distorting at this point. You have a few options, you can profile that setup and assign that profile, so it will display properly and "convert from" properly. Scanner spaces tend not to be great editing spaces, so converting to a perceptually uniform space like those you mention is a good idea.
Your other option is to bring it into Photoshop as is, and start assigning various working spaces until one looks about right, and edit from there. I believe we have several experts here who advocate this approach.
All of this can be accomplished on the fly if you like, by using the color management settings in Silverfast. But they remain so absurdly unintuitive that I'm not going to get into that here, even though I've used them for years and it works.
I'd recommend going over this site at length, particularly the section on color management settings-
http://www.computer-darkroom.com/sf5_contents.htm
Tyler
after a bit research, the thing seems to be more complicated than I presumed.
The Howtek D4000 actually has a log Amp that applying gamma curve analogously before any A/D conversion takes place.
If the scanner software is capable, then it might better off pulling data from those log Amp rather than a linear Amp, according to a letter sent back from aztek.
Thus, this creates a dillema that it might not be very wise to scan in gamma=1.0 mode for D4000, but rather seeking something that captures the log Amp data would be wiser.
Aztek keeps assuring me that their software can capture analog signal after log amp and then convert it into 12 bits of space which is far superior than most other software that scans at native data, simply applying a gamma 2.2 to correct the tones, which causing color clipping...
but their software is tooo expensive.
You may be being a bit mislead. Silverfast uses the log amp according to others that have looked into the matter in depth. Additionally you have the option of turning on a gamma adjustment of your choosing, or turn it off entirely in the options settings. Until the tiff is opened and saved in Photoshop, it remains in the native bit depth of the device.
Tyler
Are you sure that Silverfast AI has access to the analogy log amp?! According to Aztek, their software is the only one that is able to control the log amp gains and stuff. Aztek people somehow insinuated me in their email that Silverfast Ai merely grab the 12bit data and applying gamma function on them only and would cause huge digital clipping....
Even if Silverfast Ai utilize the analog log amp at some stage, how am I supposed to control it?
Thanks
You don't.
Just because a particular scanner software uses the log amp instead of the linear amp does not imply it gives user access to the particulars of it's behavior. It's use over the linear amp is because the resulting distribution of tones from the vast majority of films is preferable over the linear amp. DPL users, or anyone with other software (?) allowing that option might chime in on the differences.
Very very few scanner and/or software combinations give user control access at that stage, obviously DPL is one of them, the Nikon scanners had an analogue gain setting that was useful, but I know of no others. It was desirable with the Nikon because of it's limited density range capability, and it was often possible to use the analogue gain setting to avoid clipping with some films. It could also reek havoc if not carefully used.
Howtek and other drum scanners have very large density range capabilities. That most options give no access to user control at the analogue stage does not mean your scans will clip. I do not have that option with my setup and I don't recall a film I could not capture without clipping, maybe one bizarre cross processed pushed old thing, and just a few pixels clipped.
Despite the theoretical and no doubt practical advantages such control offers, countless thousands of amazing files are created and have been created by expert users and great equipment and software WITHOUT this feature, literally flawless work that no one could fault.
Would we all like that control? I would, but it's an unaffordable luxury personally, and from a business standpoint in my market, a totally unjustifiable expense. And I make pretty great scans thank you, with no clipping.
Get it if you can, and want, but I assure you that your scans will not clip just because you don't have it.
Tyler
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