How big is a flatbed scanned 8x10?

[Daniel Stone]

Next question: What's a "Kami" fluid? How is is used?
After 60+ years in Lf, I feel like starting my threads "Newbee wants to know...." :-)

Check out the info here:

http://www.aztek.com/kami_advantage.html

Cheers,

Dan

[SergeiR]

anywhere between 700m and 2g... scanned at max resolution in DNG will not work well, bc photoshop cant open them.. (oh how irritating that damn 2G limit is even on 64 bit version...). Resulting b&w jpeg will be about 100m

[Jim Andrada]

I'e just about given up on saving in PS format because of the 2GB limit - use a couple of layers and your 8 x 10 will be over the PS limit.

Next machine will have 64GB of memory so yeah, 2GB is ancient (and higher end servers will be coming in at over 500GB of memory soon - can >1TB memory machines be far away?)

By the way, Kami fluid is very flammable so be careful with it.

[andy]

I just scanned some color 8x10s at 16bit 2400dpi on my v750, and the files straight from the scanner are 2.4gb. (they're for 60x80" prints) normally I try to scan for the maximum print size I'll use for that image.
after some adjustment layers, they quickly shoot up, and you have to save it in large document format, or .psb,
if you're working in photoshop.
also, when I'm scanning that large, I scan directly as a .psd

I scan with a sheet of anti-newton glass, I tape the negative, base side to the glass, and then shim that negative/glass combo a few millimeters off of the scanner's platen glass(using cut up strips from an old film box)--this gives a solid scan without newton rings.

also, in terms of computer processing power, I'm using a mac with 16gb of ram, and a 3.4ghz i7 processor, and while dealing with the large files is far from speedy, it handles them without problems. The longest times are when silverfast is processing the scan. after that it's not much of a problem.

hope this helps--

[chuck94022]

Next question: What's a "Kami" fluid? How is is used?
After 60+ years in Lf, I feel like starting my threads "Newbee wants to know...." :-)

Bill,

You've gotten a couple of vague answers on the "What is Kami fluid", but nothing more specific. I'm currently in China, where the fluid is not available. I researched it a bit, and from what I can tell, it is essentially a very clean lighter fluid.

Now the Kami guys will protest and say it isn't lighter fluid, but the behavior of Kami and lighter fluid are more similar than different. Both are highly volatile - you need to be careful, because they both can easily catch fire from sparks. Don't suggest you use it if you are in a dry area with lots of static electricity.

Both evaporate very quickly - this is the "no clean up" part. This kind of distillate evaporates almost as fast as you lay it down. It disappears while you watch. Very fast.

Lighter fluid is a (dangerous) alternative. And depending on the source, you might get some residue, since it wasn't intended for this use. At least in my case, the products here in China frequently have unwanted additives just to stretch the volume. You wouldn't notice them if you are using it to light a cigarette, at least until your lighter finally clogs up. But you might see it on a negative slathered with the now-evaporated distillate.

There are some alternatives to Kami, but they are variations on a theme - a petroleum based liquid with good optical properties (clear, no color in the fluid), that clean up with varying levels of ease. Kami is the quickest, I think. But it is also probably the most flammable. (That's why I can't get it in China, the carriers refuse to ship it. They consider it equivalent to gasoline, which it basically is.)

Wet mounting film is a skill that takes some time to master. Only you can decide whether it is worth it for your scans. For me, with my v750, I mostly dry scan.

[chuck94022]

Bill, here is how to calculate file sizes. Assuming you are scanning for printing, and the printer is printing 300 pixels per inch (ppi). Don't confuse this number with the wild numbers you see from Epson and others, talking 1440 dpi, etc. Those numbers are meaningless for this purpose, and have to do with individual droplets, which we don't care about. You only need worry about printer pixel level resolution, which is going to be something like 300, or 150, or 240. We'll assume 300.

If you scan for the size print you are going to make, let's say you want to do a straight across 8x10 print.

You will need to scan your film at only 300 ppi.

Let's assume you'll scan at 48 bits per pixel, 16 bits per channel of R, G and B. This is the highest quality setting, and gives you the best flexibility later in Photoshop or whatever you'll be using for post processing before printing. This means you'll have 6 bytes (8 bits = 1 byte) of data per pixel.

So, the resulting file size will be on the order of:

Size = FilmWidth x ScanResolution x FilmHeight x ScanResolution x BytesPerPixel

or in this case:

Size = 8 x 300 x 10 x 300 x 6

So you'll get about a 43 million byte file (41.9 megabytes on disk, because 1 megabyte = 1,024,000 bytes - not an even million.)

If you want a 16 x 20 image, you need twice the resolution, or 600 ppi. So the calculation would be:

Size = 8 x 600 x 10 x 600 x 6

or about a 173 million byte file. (168 megabytes on your disk.)

If you want a 60x80, like Andy above, you need to scan at 2250 horizontally, and 2400 vertically, and since you can't do that with an Epson scanner, you'll just scan at 2400 (60x80 is not the same aspect ratio as 8x10, to get that he would do 64x80 prints, an 8x enlargement).

The file will be

Size = 8 x 2400 x 10 x 2400 x 6

or a 2.76 billion byte file. (2.69 gigabytes on disk.) I'm guessing Andy cropped to something like a 7.5x10 aspect at scan time to get the smaller file size.


To figure out how much resolution you need in your scan for a given print size, this is the formula:

WidthResolution = PrintWidthInInches / FilmWidthInInches * PrinterResolution
HeightResolution = PrintHeightInInches / FilmHeightInInches * PrinterResolution

Choose the larger of the two numbers if they are not equal. (They won't be equal if you change the aspect ratio in the print, or if the printer doesn't have square pixels.)

[Bill_1856]

Mein Gott, that's gotten complicated!

[chuck94022]

It puts wet printing in a darkroom into a whole new perspective, doesn't it?

[rdenney]

Bill, it's simpler than you think. If you scan 8x10 at the same resolution as you scanned 4x5, the file will be four times as large, because there is four times the area. If you scan it at half the resolution, say, 1200 vs. 2400, the file will be the same size because you'll have one-fourth as many pixels in each square inch.

So, doubling the linear pixel dimension--either by doubling the film size or doubling the resolution--increases the file size by a factor of four. Halving the linear pixel dimension--by halving the film size or halving the resolution--decreases the file size to one-fourth what it was.

Color is three times the file size of black and white at the same bit depth. And doubling the bit depth (going from 24-bit color to 48-bit color, or 8-bit grayscale to 16-bit grayscale) doubles the file size.

Scan files sizes (in bytes) are typically six times the number of pixels for color, and twice the number of pixels for black and white.

I scan 6x7 in my Nikon film scanner at 4000 spi, and 4x5 in my Epson at 2400 spi, and both files end up with about the same pixel dimensions and are therefore about the same size (500-600 MB for 48-bit color scans).

Rick "two miles square is four square miles" Denney

[ImSoNegative]

would the kit for the v750 work for the v700?