View Full Version : Imacon Sharpening
Imacons method of sharpening is to covert the file to LAB, select the Lightness channel and sharpen that channel only and convert back to RGB color (or back to Grayscale). Does anyone understand the advantage to this. For Color or B&W?
That's a fairly standard technique (some advocate always doing that for sharpening). It is supposed to reduce color noise as minor shifts in color in the sharpened areas. The two conversions introduce rounding errors, though, and if you do it in PS, it is best done by doing a Fade in Luminosity mode.
What QT said.
By sharpening in the L mode, you avoid sharpening the A & B channel color data....which lessens the appearance of of chroma noise....typically red and blue spots like film grain.
So there is no advantage to doing this with a grayscale image. I have tried it with a grayscale image and a b&w RGB file comparing the sharpened original file vs, sharpening just the L channel and can see no difference at all.
Kirk, that's right. For a greyscale image, or for a color image with no significant data in the A and B channels in Lab mode, there's no advantage at all.
I am trying to understand this as a friend of mine just bought a 949 and we are going to start testing it next week.
ANYONE who just bought a 949 would be my friend too.
Sharpening with this method can make a difference for grayscale if you're converting from color to black and white by channel mixing or in calculations. The idea was originally dreamed up to smooth over the horrible grain and noise patterns of the first digital press cameras sold to newspapers.
Going to Lab also offered the technical opportunity to click on the A and B channels individually to check for random digital noise, then smooth those patterns with the 'dust and scratches' filters.
Almost all of the modern scanners and digital cameras have built-in noise reduction and sharpening, or at least they try. However, those who had to learn the hard way when the first digital equipment came on the market still have a habit of checking those channels to see where the noise is.
We also did most of our light/dark toning in the Lab channel-lightness selection because we could actually lighten the image for production without a color shift.
Amen! He owns an international web based film recorder business, Gamma Tech. He needed to reinvest some profits before tax season. After I work with him awhile he will be offering high res 4x5 scans for $30.00 mailorder.
John, interesting!-next time I have some noise issues I will check that out.
Kirk. Was that a typo? $30.00? 4x5 High Res? He wants to start his own religion and needs followers, right?
That was not a typo. I will be working with him to make sure he is doing what he can to satisfy the needs of LF people and I will let you know when the service is up to snuf (where did that phrase come from?).
"$30.00? 4x5 High Res?"
$30.00 is a reasonable price point. I've been scanning 4x5s for friends on a 646 for $27.00. I arrived at that price based on $20.00 per hour for time and depreciating the equipment over three years. I'm not making a profit (just convincing my wife that the purchase was a "business" expense). But I'm also not doing a high volume. At $30.00 for the 949 (faster but more expensive) and a reasonable volume of work a reasonable margin should be possible at $30.00.
The old pricing structure for drum scans (i.e. $0.50 per megabyte plus a setup fee) is base the labor intensive wet mounting process and the slower throughput of that equipment.
Regarding Kirk's original question: I have been able to mimick the Flexcolor sharpening effect with Photoshop but it takes a dozen more steps. I haven't compared what happens with greyscale work.
Just curious if you have the time. What are the steps?
Kirk, if you're asking me, I'll email you something tomorrow.
Yes John sorry to be vague.
Kirk, I've emailed several things to you.
Knowing what the prices and quality are on the global market, I'm not particularly impressed by the $30.
We do our Flextight 949 scans from 4 by 5" film to 476 Mb (16 bit scans) (this biggest optical res you can get from the Imacon) for Australian $25 (about $18 of your US dollars I think).
Less for bulk as well by negotiation!
Of course, you have to send your film to Australia, but many people are doing so without trouble!
Image Science Flextight Scanning (http://www.imagescience.com.au/Scanning/Flextight949.php) direct link.
> We do our Flextight 949 scans from 4 by 5" film to 476 Mb (16 bit scans) (this biggest optical res you can get from the Imacon)
Does this work out to about 2200 DPI?
QT comparing Imacon scans advertised on line it is definitely at the low end price wise of of what is advertised out there. What are you refering to.
Jeremy has given you a good example. He is from Australia. As everybody knows, there are countries where labor is much cheaper than in Australia.
2040 PPI is the max optical res on an Imacon 949 with 4 by 5" film.
It's very sharp with it (even with the software sharpening set to off, yes I know the -120 trick), so you really get your 2040 PPI, unlike say those Epsons which are considerably less capable of resolving detail at their claimed 4800 PPI than the Imacon at 2040 PPI.
For the very biggest prints drum scans are probably still the way to go if you can afford them and find a decent operator which can be difficult.
Yes, there are countries with cheaper labour than Australia! But Australia has a very safe postal service, the language spoken is English which aids clear communication, and it's always a balance between getting someone who cares about their work and getting the cheapest possible price. Even by international standards I think we offer a very good price/performance ratio.
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