** Reply to note from "Ian Welton" <[log in to unmask]> Sun, 10 Sep 2000 15:32:44 +0100


> Question.   Does a digital image constitute a photograph for the = 
> purposes of the law?  There may be a difference here between moving = 
> digital images and single frame digital images. 
>  
> Considering the process and technology used to initially capture the = 
> image it would appear yes. (i.e. lense and photosensitive = 
> paper/plate/cell of some description.) 
>  
> Considering the treatment used to process the image following that = 
> initial capture it would appear that a digital image is not a photograph = 
> as currently defined by the dictionaries. 
>  
>  
> Views eagerly awaited.

Such a question such a looooooong reply :-)

Hi Ian,

No legal explanations here, just a bit of "photography" (going back to
my roots).

If you are looking for the "scientific" difference between the two
processes there is 1 basic difference. The capturing medium.

In photography the use of light is used to alter the properties of a
chemically coated plate.  (You don't need a lens, eg. pin whole
camera).  How you reproduce from there on becomes irrelevant (more
later).

In digital image capture, again you have light captured by whatever
electronic thingie-midgies inside the box (technical term this).


Until we have developed the chemically coated plate (film or paper or
..) or until we have stored the digital image from RAM as a file on a
hard disk we don't really have an image.


I think they all turn to an "image" when we can see them.  That is,
see a slide, or a negative, or a negative "developed" to a positive.
See a video tape played back, or see a digital image on a TV or
PC screen.

===========================================

At this point technology gets very mixed indeed and you may have
difficulty arguing that for the purposed of DPA electronic
capture/storage of images does not constitute photography.

Ordinary film based cameras can take digital backs (eg. Nikon,
Hasselblad) which are capable of producing exceedingly good results
(in terms of resolution).  

Slides can be digitised, and negatives converted to positives whilst
being digitised.

Example.
You can have a negative, turn it to a positive digital image, and say
manipulate it with something like Photoshop.

Most people think that you can only print a digital image on a laser
or inkjet type printer.  False!  The best (and most expensive) way of
printing a digital image is by converting it to a negative or slide
and printing it using photographic methods.  Reason:  Photographic
reproduction will reproduce evey pixel of the digital image (now film)
and photogaphic reproduction a has longer self life than any other way
of reproducing images (eg. laser or ink jet printers).

At this point we have hybrids of a digital image or a chemically
produced image.

===========================================

Just to mix everything a bit.  What is then infrared photography which
does not use "light" whether captured on a chemically coated plate or
with some electronic gadget?

What if video recording onto a video tape (is this classed as digital
capture? why do I think it is analogue whatever the difference).

I would not get mixed up with (sequential) images and single frame
images.  All motion depicting images are single frame images shown in
rapid succession.  In cine terms, we have only to see 24 stills per
second and we see constant motion.  Home television works at a much
worse rates/resolution to con us into seeing motion.

============================================

Where do you get these weekend brain teasers?  I guess everyone has a
hobby.

Not really seeing what you are driving at, is a picture on a newspaper
depicting a person a "photograph"?  We don't know how it was captured
(ok, with a camera, but it could be digitial or conventional).  And it
has been reproduced (on the newspaper) through a digitised image
through an electronic photosetting gadget, printed through a
mechanical process (and chemistry might come somewhere on the ink side
of things).

I don't know about you, I must be mad trying to answer this  :-)

Regards
Charles

PS.
If you like more thoughts :-) I will be out of the office for a while
but I will try to check my mail once a week.

==============================================
Charles Christacopoulos, Secretary's Office, University of Dundee, 
Dundee DD1 4HN, (Scotland) United Kingdom.
Tel: +44+(0)1382-344891. Fax: +44+(0)1382-201604.
http://somis.ais.dundee.ac.uk/
Scottish Search Maestro http://somis2.ais.dundee.ac.uk/


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