Scan B&W in full-color mode?

[mark_ehlers]

In the Jan/Feb 2008 issue of "Photo Techniques" magazine, in his article "The

Right Way to Scan" Ctein states that we should scan our B&W negs in full-color

mode on the scanner, then do the conversion on the computer. The result is

apparently less noise since the scanner only uses one channel (green) when

scanning in B&W mode. This is news to me. I guess it makes complete sense. Does

anyone have comments on this?

[jordan_w.]

It totally depends on what scanner you're using. With both of mine, I've found no advantage in scanning in full-colour mode.

[kelly_flanigan1]

This *secret trick* was the rave in service bureaus in the early and mid 1990's with flatbeds and other color capture devices such as a Fiery based color copiers slide/print scanner. The *trick* was that the software was klunkier; the hardware cruder and a color of B&W sometimes was better for dynamic range and or shadow or highlight detail. A second ancient *trick* was to scan a poorly exposed positive as a negative or vise versa to capture details. These methods are typically not effective in modern scanners with better hardware and software; but are worth exploring. To sombody new to scanners these old methods are debunked; like ancient methods to start a 6 volt car in the 1950's. Many times in servoice bureau work long ago we just got better scans than a customer not due to better scanners; but due to Kentucky windage; futzing; due to using the scanners more. Its amazing that Barry Stein is mentioning this ancient method in a 2008 article. Unless the scanner/software is known in may be not effective anymore; it is mostly not on many of my scanners. Barry Stein was writting technical articles and manuals before he started his more recent Photography gig. He is interested in astronomy and telescopes too.

[William Kahn]

The one advantage I've found in scanning B&W negatives in 48-bit color mode (Microtek Artixscan 1800f, Silverfast Ai Studio) is in making the filter options usable in CS3's B&W conversion tool. I've tried scanning in 16-bit grayscale, then converting to RGB in CS3 to make the filters usable. It doesn't work. You can, however, apply sepia toning that way.

[kelly_flanigan1]

With a 36" wide color scanner we have thats 8 months old the scan menu is truncated for a greyscale versus a full color scan. Thus I often scan a 36x36" greyscale image as a color one to have a better menu that makes it easier to set exposure, thresholds, adding more paper space. Thent eh image is converted back to B&W in photoshop aafter scanning. The color scan is just to get around klunky software that boxes you in to a corner. One can scan at 200,300, 400, 500 or 600 dpi accross the full 36" width; so files can be decent in size.:)

[kelly_flanigan1]

The scan as B&W as color; and scan and invert schemes get asked on Photo.net and others boards every blue moon. Typically yea or nay answers come out; depending on the persons equipment; or biases. These tricks do work on some scanners thus saying it never or always works works is narrow minded.<BR><BR> These tricks were written up in a technical article for Shutterbug a decade ago as a possible way to improve scanning; and were rejected with a reply "We tried it it just doesnt work" by B.S.; ie Shell. Thus if one wants a B&W world one can say Barry or Shell is right or wrong; or one can actually try one's own gear instead of thinking everything in the world fits in this orderly behavior.

[Ed_Ingold]

All scanners scan in color, then downsample to a grayscale image. However, there's no advantage to scanning in color if the original is B&W. A greyscale image is only 1/3rd the size of a color image.

 

If you are scanning color film, then scan in color and convert in Photoshop (or whatever). This way you can weight each color according to the sensitivity of B&W film or emulate the effect of various filters. (B&W is about twice as sensitive to blue as to red or green).

[william_john_smith1]

<I>Flanigan said: Its amazing that Barry Stein is mentioning this ancient method in a 2008

article.</I><P>It is not Stein but Ctein, who is one of last dye transfer printers left on this

planet. He does know a thing or two about color, printing, scanning etc.<P>The best way to

find out is do it yourself, only you will know what works with your equipment.

[kelly_flanigan1]

Edward; with some older film scanners one could get a slightly sharper image when scanning in color than B&W; with a B&W negative. Our older Canon FS2710 was like that somewhat. This unit had many many versions of software released by Canon for its earlier version(s) of the 27xx dpi unit; some early versions were horrible; and scanning a B&W negative as a color one was radically better..<BR><BR>On ancient flatbeds the dynamic range was lower; often it was hard to get details in the deep parts of a print. By using the color scan software it allowed one to pull out pesky shadow detail better than the straight B&W mode. The lower tier Mustek 11x17 flatbed we got back in 2000 was like that. The dynamic range of the unit was way poor than an Epson. With a dark print to scan one could select the color scan setting and one could capture greater detail in the shadows; because the software allowed one to go further into the muddy black. Its not that really color is better; its that the lame scan software often is dumber in B&W modes with some scanners; the range of exposure tab deals are truncated. Our brand new 36" wide color scanner I mentioned earlier is like this abit too. With it one can blow subtle highlights that are almost the same as a print's whiteness when in B&W greyscale mode; versus color mode. Thus one uses the color mode just as a way to scan without losing highlight detail. Once in photoshop one can then set the levels; due curves; and convert to a 1/3 sized greyscale image. Many of these units run in a dumber mode in B&W.<BR><BR>With the older Fiery based 400dpi flatbed 11x17" unit/35mmm slide scanner; the scanner scans a color image with 4 separate scans; one pass for Red; one pass for Green; one for Blue; one pass for Black. The original sees 4 passes when in color mode; and 1 greyscale mode. Thee service contract actually logs color scans as 3 passes ; one for R; G and B; and the fourth counter for the grey pass. One can scan only in blue; and the blue counter does up with each pass. A greyscale ie B&W scan has only one pass of the scanning mirror. In this old unit the original is fixed; a flat mirror moves in the 17" dimension; a focused long path scanning beam came from a rotating many sided mirror. One can scan an original in Red only if wanted and save this file; then scan it again in Blue etc too. <BR><BR>In our several 36" wide B&W only scanners; the newer ones scan in greyscale; the ancient ones in B&W bitmap; ie no grey. The greyscale models scan in grey; but the light source does have some color blindness a tad. Thus one unit may *see* a yellow highlighter as a darker almost black grey compared to another greyscale scanner.; or one unit is better than another for scanning a yellowed old map.<BR><BR>Here I have 5 scanners that scan in grey or bitmap only; with no color info at all. These are normally used for aerial photos; drawings, maps, and scanning B&W photos. <BR><BR>The advantage of scanning a B&W original in color has been known and used since the early 1990's. It once was abit of a trade secret; a way to pull out shadows and highlights in originals; when scanners and software were in the dark ages. Often one really has just more control when doing a color scan. In some ancient flatbeds the light source actually ran at a different level when in color mode; and it did a recalibration of the source more often when in color mode too. I remember chatting with folks about this back in 1993 at the irga converence in Reno; the Concord landed at the airport; darn it looked small. <BR><BR>In ancient scanners like the color one they had at Blair Graphics in Santa Monica about 1995; the unit was on a old process camera; with each monochrome scan done with a color filter over the lens. One did a scan; then swapped out the filter; then did another scan; one for each color. Alot of ancient Hollywood color movie posters wer scanned this way at Blair.<BR><BR>In scanning of B&W maps in color mode; one can often have a radically better way to *back out the yellows* ; *back out a funky color paper background.* One uses the color mode as just another tool in scanning. In the pure process camera era; one often tried colored filters on poor fade originals; to goose the blues darker; to depress the yellows. <BR><BR>With the Phase One 4x5 back one can leave the IR filter off and shoot an original painting in visible and IR. This sometimes will show hidden rework; or a hidden signature; or layout lines. This technique is used even on B&W images and sketches; the extra IR tool can sometimes reveal extra info. <BR><BR>

[kelly_flanigan1]

William; before his photo book writing adventure his name was an alias; not a legal name but a nickname. His older name(s) were used in the SF astronomy gigs not his alias. Maybe if Hillary changes her name tommorow to savior of the planet some folks we still remember her has Hillary; and call her by her (obsolete) name. Alan/Barry or whatever is really into sci-fi; astronomy, ufo stuff, fantasty conventions. Just because I met somebody eons ago before the name change event is no reason correct folks for using the name the chap used awhile back; one that they used to introduce themselves with. Its like having a friend in college named Joe 15 years later be known as Cjoernx; and you are a duffus for using his old legal name. Heck I still call film *film* no matter if the world is hell bent with analog term. Maybe this is a different Caltech Physics chap that was with a Paula at a astro event eons ago that talked about sci-fi; and didnt go by the new name? Maybe then older Caltech Physics chap was taken by aliens; and the clone is now the the C guy; with the C for clone?:)

[obakesan]

Hi

 

this is interesting news. I've just bought an epson 3200 on ebay cos I'm in a different continent to where my epson 4870 is, and I'll be interested to experiment with this. Especially given that the 3200 has often been ranked inferior to the later models (and the reason I purchased the 4870 when I did).

 

I'm mainly going to be scanning 4x5 ADOX with it. I'll post my results and given Edwards interesting insights added I'll post histograms of all three channels.

 

thanks for asking such an interesting question. keeps me thinking outside of the 9 dots