[Leica] Tina and Digital (was, Enlarger

[bdcolen at comcast.net (B. D. Colen)]

Okay, I wasn't going to post this unless this started up again today...but
since it has....(and all due respect to you, Barney :-) )
...
This is perhaps the single most inane thread ever to take up LUG bandwidth.
:-) 
 Tina is not a techie. I am not a techie. Ted is not a techie, nor are most
of the hundreds of other people on this list who have figured out - mostly
on their own by trial and error, just as they learned wet printing - how to
do digital printing. (Nor for that matter, are the 10s of millions of
average Joes who are buying off the shelf printers and turning out as good
prints as they got from CostCo in the past). I don't know about the rest of
you, but I've never taken a course, never read a manual, but have learned
what I've learned from talking to friends, experimenting, and reading a part
of a chapter in a book here, and a part there. (Oh, and I've never
downloaded a RIP, and until reading the explanation posted here, never knew
- or much cared - what it stood for other than "rest in peace.") And by
simple trial and error - the same kind of trial and error by which we
learned how to make silver prints - we've learned how to produce various
types of high quality digital prints.

To have Marc Small, who reminds us with his Email address that he is a Yale
alum, who has reminded us repeatedly that he is an attorney, who can tell
you the difference between a NOOKY and a SNOOKY, and who knows how many
screws hold together the Leica A manufactured on the afternoon shift on a
particular Tuesday in November in 1932, to have that Marc Small tell us that
he just can't figure out this damn complicated digital printing stuff,
smacks just a tad of something from "Three Billy Goats Gruff."

If Marc, or anyone else wants to stick with wet printing, more power to
them; black and white fiber prints can be spectacularly gorgeous, different
from anything produced digitally. But such prints are becoming, with every
passing day, more an artifact of an earlier era in photography than the
modern photographic standard. Of course whether that's good or bad is fuel
for another thread.


On 2/7/06 12:28 PM, "Barney Quinn" <bquinn@sgi.com> wrote:

> 
> 
> Marc,
> 
> I'll give this a try. There are, in general, two ways to store an image on 
> a
> computer. One is called vector format. In vector format you don't store the
> image, you store the instructions for making the image. In the old days a
> vector, in basic physics, was a line which had both magnitude and 
> direction.
> In vector graphics you store an image as a set of instructions which say
> things like draw an orange line from this point to that point. This is how
> postscript works. It is a set of instructions which describe how to make 
> the
> image in question. Postscript files are plain text files and if you want 
> you
> can open one up with a text editor and actually look at the instructions. 
> If
> you are really adventurous, and if you know postscript very well, you can
> even take a text editor or a word processor and write out all the
> instructions to make an image out by hand. But, all you need to remember is
> that in vector graphics you don't store the image, you store the 
> instructions
> for making the image. It's the recipe, but not yet the dinner you are going
> to serve.
> 
> The other way to store or represent an image as as what is called a bit 
> map.
> This works the same way as a picture in a newspaper does. The image is 
> broken
> down in to a bunch of dots. Each dot is stored as a number, or a series of
> numbers, which represent the things you need to know about the dot such as
> its color. These dots are usually called pixels. You could store a very 
> crude
> image by breaking it down into a series of dots which were either black or
> white. If you represented each black dot with a zero and each white dot as 
> a
> 1 then you could store the entire image by storing the 1's and 0's which
> represented the image as a file on your computer. This is exactly how 
> digital
> photography works, only more information is stored because you need more
> information other black or whit to make a continuos tone image. If you 
> wanted
> to compare an image made with just ones and zeros to conventional 
> photography
> it would look like something printed on litho paper because there would be 
> no
> grays. In a slightly more sophisticated system rather than describing each
> dot or pixel with a 0 for black or a 1 for which we could describe it with 
> a
> number from 0 to 7 where the numeric value told us how gray the dot was,
> sorta like the zone system.
> 
> There is a tug of war going on between these two approaches. Vector format 
> is
> useful for some things, such as line drawings, of a page of text, because 
> it
> takes less space to store the instructions to make the image that in would 
> to
> store the actual image. But, as an image becomes more and more complex you
> need more and more instructions in order to store it in vector format. In 
> the
> case of something like a photograph the amount of space you would need to
> store the instructions to make the image can get to be more than the amount
> of space needed to store the image as a bit map. What this means is that it
> takes less space to actually store the image than it does to store the
> instructions for making the image. There is a slight complication here, 
> which
> we will not go into at this point. Imagine a black and white image with a
> high white cloud in it. That is a lot of white, and it takes a lot of 
> numbers
> to describe it.
> 
> There are techniques, called data compression, which will let you store the
> image of the cloud without actually having to store all the ones and zeros
> which make up the cloud. This is called data compression. But, here's an 
> idea
> of how it works. Let's say you wanted to draw a line which ran vertically 
> up
> and down the page which was ten inches long, and let's say that you made 
> your
> image by storing 300 pixels, or dots, for every inch the line was long. In
> the real world computers store information using groups of eight 1's and 
> 0's
> called bytes. In the most basic real world graphic systems one dot, or 
> pixel,
> is stored as a byte or group of eight ones or zeros. To represent the ten
> inch line would take 10 times 300 pixels, or 3,000 bytes of space. It 
> takes a
> lot less space to say start here, and go north for 3,000 dots. The first is
> bit format, the second is vector format, and the difference can be thought 
> of
> as data compression.
> 
> Here's where the rubber hits the road. A bit mapped image is just a bunch 
> of
> ones and zeros stored inside your computer. A vector image is nothing more
> that a set of instructions showing how to draw the image. Neither is an
> image. Both are just a lot of data which is unintelligible to a human. To
> actually get a picture on the wall it has to be printed. This is done with
> something called a rendering engine. Computer geeks use the term engine 
> for a
> program which does the same task over, and over.
> 
> The easiest way I know to answer your question about the meaning of the 
> term
> RIP is to consider what happens when a line drawing is printed out on a 
> piece
> of paper. Let's say that you are using a printer which prints its images at
> 300 dots to the inch. What that means is that a black square one inch by 
> one
> inch would be made up of three hundred dots across, running from left to
> right, and this would happen 300 times running down the page. When the
> printer printed the image it would start and put 300 black dots on the page
> running from right to left.  Then it would finish running across the page.
> The print head which made the dots would move back to the left hand side of
> the page, and page would be advanced 1/300 of an inch, and the print head
> would make 300 more black dots. This process would repeat it self until 
> both
> the one inch by one inch square and the page had been completed. This 
> should
> also give us a hint about why this is am important question. A black square
> an inch by an inch at 300 dots to the inch is made up of 300 x 300 or 
> 90,000
> dots. The amount of information you have to store and manage goes up by
> squares as the size of the image increases.
> 
> A TV set makes an image by sweeping a beam of electrons across the screen,
> causing the appropriate "dots" to "light" up as it goes. When it is done 
> with
> the first line it skips down a line and does another. It works its way down
> the page first doing all the odd numbered lines and then comes back up to 
> the
> top and does all the even numbered lines. This is called interlacing, and 
> we
> aren't going to go into why it's done that way today. This pattern or 
> across,
> down, across, down, across is called a raster. I have no idea why. A 
> printer
> works the same way, only it doesn't skip lines. It does the first, then the
> second, then the third line. Because of the similarity of how a printer 
> and a
> TV work people started calling an image inside a printer a raster, too. RIP
> has three meanings which I know of. The first is Rest in Peace. Most people
> by now are probably wishing I had done that five paragraphs ago. The second
> is Raster Image Processor, and the third is Raster Image Profile.
> 
> All printers have A RIP, or raster image processor built into them. Let's 
> say
> that you want to print an image which is stored in vector format. First you
> have to convert the instructions for making the image into ones and zeros 
> or
> pixels. This is done by a piece of software called a rendering engine. In 
> the
> case of postscript the instructions which make up the image are rendered by
> something called a postscript interpreter. In the case of a compressed bit
> map image the image has to be uncompressed before it can be printed. The
> resulting ones and zeros are now handed to something called a RIP, or 
> raster
> image processor. The RIP converts the ones and zeros into the back and 
> forth
> and up and down instructions that the printer needs to actually put the 
> image
> on paper. Every engineer on the list is probably cringing at this crude
> generalization, but it is the basic idea.
> 
> Now, to the other meaning of RIP. Raster Image Profile. The world is not an
> ideal place, Physical systems are not ideal. Corrections need to be made to
> the information stored in the computer which represents the image in order 
> to
> get it to look "right" when it is printer out. You might, for instance, 
> have
> to make the red's a little bluer in order to get them to look right. The 
> best
> way I can explain a Raster Image Profile is that it is the set of 
> corrections
> which must be made to get the image to look "right" in the real world 
> using a
> specific printer and piece of paper. If is very much like the orange mask 
> in
> a color negative, or the correction pack which you use during color 
> printing
> to compensate for things to get the image to look proper.
> 
> May God forgive me for this unending string of over simplifications. I hope
> it helps.
> 
> Barney
> 
> 
> 
> Marc James Small wrote:
> 
>> At 05:25 PM 2/6/06 -0800, Frank Filippone wrote:
>>> Think.... RIP= Ripped O..
>>> 
>>> That is pretty close, and 60's Lingo, so that should work for you....
>> 
>> I am even more lost.  "Ripped Off Plums"?  I am really at sea here and the
>> boat is sinking rapidly.  I do not need hints.  I need reality.
>> 
>> You folks are not being much help at all.
>> 
>> Marc
>> 
>> msmall@aya.yale.edu
>> Cha robh b?s fir gun ghr?s fir!
>> 
>> NEW FAX NUMBER:  +540-343-8505
>> 
>> _______________________________________________
>> Leica Users Group.
>> See http://leica-users.org/mailman/listinfo/lug for more information
> 
> --
> Barney Quinn, Jr.
> (301) 688-1982 (O)
> (240) 535-3036 (C)
> (877) 220-0981 (P)
> 
> 
> 
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