Colour Transparencies - & recycling them

[Gordon]

...however I would suggest you get them re-done as probably lost some definition by viewing the wrong side of the emulsion (esp for Kodachrome which has quite a thick layered emulsion but was always my favourite (tho very slow ) for slides)

I would not disagree in principle but in practice a professional outfit should have a decent enough scanner that has a depth of field adequate to dealing with Kodachrome "thick" multi-layer transparency emulsions and a sufficient number of dots per inch [dpi] to capture the image content of the emulsion. But what is that? I found out by experiment and it varies with how good the camera was etc but it needs to be quite high – see below. At first I used an Epson and then an expensive Nikon scanner [I don't have them any more] with high enough dpi and it was obvious that the scanner was never the problem with resolution and depth of field.

Apart from the obvious quality of a decent camera and lens, resolution "loss" was lack of basic photographic technique ie adequate depth of field etc - this is a very common basic error made by people expecting sharp images with target distances well out of kilter with the lens aperture and light level, this worse with long length lenses - moving targets, camera shake and simply the fact that early multi-layer colour emulsions did not have the resolution anyway – 35mm black and white is much better. If the scanner lets you see the grain sharply the rest is down to technique. Professionally taken photos should be better of course than amateur ones by minimising all these factors' influence. There is no substitute for lots of light [+ flash perhaps], fast shutters and small apertures and of course fast film BUT there also lies compromise.

Assuming 35mm film [whose image size is smaller than some other formats being only about 34 x 23 mm or 1.43 x 0.95 in, an aspect ratio of about 1.42] then if scanned at say 400 dpi [typical of scanning images and documents for computer storage] then each image would need about 0.2 Megapixels. This is possibly good enough for images from a cheap camera or perhaps prints. This computer’s display is only 1280 by 1024 pixels or just under 1.3 megapixels. “Full” HDTV displays are 1920x 1080 [note different aspect ratio of 16 x9 or 1.77] or about 2 megapixels with UDTV [future] requiring 4.

As a comparison modern digital still camera imaging devices routinely offer as much as 15 megapixels or even more – but that is the limiting potential. That's 75 times more than you’d get at 400 dpi. To emulate 15 megapixels [some manufacturers cheat and claim 15 but this is shared between the RGB/YUV colours so each pixel only actually gets 5 megapixels or even 3.8] a dpi of about 3,250 is needed and should of course be reflected in a printer!! Such a dpi means slow scanning though and huge files - typically each pixel takes at least 3 bytes. Interesting that large megapixel cameras can use jpg to contain file size but too small a jpg file compromises the high pixel count!! And beware Dave's warning in #6.

[umslopogaas]

Phew. Many thanks Gordon, one of the pleasures of this website is that you enter a discussion, not knowing much, and find that there are people out there who know an AWFUL lot. I will try and digest this information, but I am from the Canon F1 very expensive lenses and Kodachrome 64 age, all this modern stuff takes a bit of getting to know. I was actually delighted to discover a month or so ago that Boots actually do still sell 35 mm slide film.

[Gordon]

Phew. Many thanks Gordon, one of the pleasures of this website is that you enter a discussion, not knowing much, and find that there are people out there who know an AWFUL lot. I will try and digest this information, but I am from the Canon F1 very expensive lenses and Kodachrome 64 age, all this modern stuff takes a bit of getting to know. I was actually delighted to discover a month or so ago that Boots actually do still sell 35 mm slide film.

I know the feeling, when other erudite folk here wax lyrical about subjects - the arts and music at a technical level - that are out of my experience I find it both humbling but also educational. My technical knowledge came from many years working in the telecomms and broadcasting field being involved in designing and using professional TV and audio equipment.

That Canon F1 is a good camera - I have my Minoltas and lenses still but rarely use them now, worthless second hand. Good to know one can get colour film at Boots!! I used to keep some in the fridge but it all got so out of date that it was dumped some while ago!! I now have a Canon digital and find it more than adequate. You have done well to preserve those slides; in the climate of PNG the heat and humidity would be the greatest enemy with a strong risk of mould. I have some Ektachrome slides from the mid 60s inherited from father in law and they look fine!

[umslopogaas]

Gordon, the humidity at Keravat was saturated, the slides would have gone mouldy in a week if I'd kept them in my non-airconditioned house, but fortunately I was able to store them in my airconditioned office. The oldest were kept for eleven years in that environment, but barely a trace of mould. I had a large silica gel desiccator to store the camera. I also had an Ikelite perspex housing for the camera, and used to take it scuba diving. With two flashguns attached it was an unwieldy thing to swim around with, but I got some good photos. It never leaked, though it came close once when I hadnt done up the clips properly, but fortunately I noticed just in time. Digital cameras must have transformed underwater photography, in the days of film you couldnt, of course, change film underwater, so were limited to 36 pics per dive, unless you had one of those cameras that took extra large rolls of film.

[kernelbogey]

Recycling unwanted slides
My nephew has just had all his Dad's (my late brother's) slides digitised and now doesn't want the hard copies - he's seriously ruthless about decluttering (and so a good influence on me as I too age).

I've urged him to recycle them if possible rather than putting them in a bin which will lead to landfill - an idea to which he is sympathetic.

Does anyone have any information - better still experience - of getting this done? The majority will be in plastic frames, but I dare say there are some from the 1960s onwards that may be in glass. My brother took all his photos over 60 years on diapositive film.

I'd be grateful for any and all thoughts on this - thanks.

[Andrew Slater]

Not much help, I'm afraid: I've inherited over 6500 of the things, (some of) which I'm planning to digitise. After that, I'll have the same problem. My initial thought is that they won't be recyclable for the same reason as conventional prints, as they contain various toxic chemicals. It would be possible to separate the plastic frames, but then they're unlikely to have a triangle 'type' marking, so won't be recyclable, by my local authority at least. The older cardboard frames would be recyclable. Also any glass, once separated, should be recyclable. How about eBay? Somebody might be interested: it depends what's on them.

[kernelbogey]

Thanks, Andrew: food for thought. There are hundreds, so I'm sure we won't be spending time taking them to pieces! I've had a brainwave this morning - I've written to my brother's professional association to see if they want the (large) proportion of them relevant to his work.

(I have long believed - not sure why - that you're in the US: is that correct? PM if you prefer.)

[Dave2002]

Difficult to know what to do. Personally I'd probably be tempted to just put them back in a box, and store them yet again, but that's yet more hoarding.

One other suggestion is to select photos which might be of interest, and print them off from the digitised copies. It's much more likely that people will look at photos in some printed form - maybe a family album or book, than stored in a computer compatible digital form. The problem one faces after a few years is that collections get dispersed, and then trying to remember - if one ever knew - who the people were in photos becomes next to impossible.

Similarly also for events - why were they important, and to whom?

Of course it maybe only matters for a "short" while - maybe 50 or so years. Most of us haven't a clue what our ancestors looked like beyond a century - or even care.

[kernelbogey]

Difficult to know what to do. Personally I'd probably be tempted to just put them back in a box, and store them yet again, but that's yet more hoarding.....

Thanks Dave: it's not my call, although your thoughts are relevant. My nephew is determined to get rid of the physical slides. I hope to do some kind of 'labelling' etc of family photos within whatever the parameters of the digital archive can accommodate. But even these are unlikely to interest anyone beyond the generation of my nephew and his cousins - who are all computer-savvy. And there are hundreds of them (slides, not cousins ).
Bestio
KB

[Frances_iom]

sometimes such slides can be very useful to local historians - it may be worth checking with your local library - certainly on IoM those slides from 60s and before can show buildings now gone and record events not otherwise recorded

[kernelbogey]

sometimes such slides can be very useful to local historians - it may be worth checking with your local library - certainly on IoM those slides from 60s and before can show buildings now gone and record events not otherwise recorded

Thank you Frances. I've been in touch with my brother's professional association, who are provisionally interested in our gifting them the large proportion of the collection - buildings and townscapes. If that doesn't work, your suggestion is a good default idea.