Detailed Information
The Art and the Science of Scanning Slides and Film
The Process
Scanning of slides and film is NOT a straightforward automated process. I do not feed a hundred slides into a machine, press a button and come back an hour later.
Each slide is looked at individually and decisions are made as to how to process it.
I will give each slide a gentle cleaning to remove any dust and put it through the scanner using a resolution of 2000 dots per inch (dpi). With a first-rate slide this may well produce a satisfactory result. However it is surprising how often there is ingrained dust or other marks that I cannot physically clean. In that case I will use an infra-red system known as ICE4. What this does is take an infra-red picture of the imperfections and subtract that from the main image. This will often produce a striking improvement. There are then other technologies that recognise the film type and make consequent adjustments affecting colours, fading and grain.
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| a not uncommon scattering of dust | the result of cleaning using Digital ICE |
After that I have another look at the picture. I will consider whether some careful minimal digital adjustments could improve the image of a sound slide. Now I'm sure that your slides (like mine!) are all perfectly exposed but sometimes I come across a customer's slides that could actually benefit from a slight adjustment to the colour balance or the light/dark balance etc. I will not be doing any air-brushing-type 'improvements'. I will remove as far as possible any surface dust or marks that were not removed by Digital ICE. I will fix any 'Red Eye' problems. I will fix any obtrusive grain problems as far as possible. But if your slide is out-of-focus the digital image will be the same. Please note that this is not intended to be a digital restoration service. Sometimes slides have deteriorated such that there are blemishes over an extensive area. In this case the digital image will simply be a faithful copy of the original, warts and all. If you need further restoration work doing on a photo, I can recommend a restorer.
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| Is there anybody there? A dreadfully underexposed low-light slide | The result of digital adjustment: not a perfect picture but the owner was very pleased to see it. |
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| Better after Digital Ice cleaning. But there's a definite colour cast. |
Colour cast corrected. |
After these adjustments, I save the file as a TIFF file. TIFF is the pre-eminent format for image files and is 'lossless' - however many times they are edited there is no loss of detail. The final version of the TIFF file will be put onto a CD or DVD called 'Archive'. The files on the Archive disk are large - generally around 14 MB and are not intended for daily use but to be stored for the future. It is common practice to save space on the disk by compressing the file losslessly using LZW compression. However as this is a proprietary compression format it cannot really be expected to be usable in the very long term and I do not use it. When you receive your Archive disk please check that the disk is OK and readable before putting it away. Let me know at this stage if there are any problems.
Finally I convert the images to JPEG files. JPEG is the commonest format used in digital cameras. (The filename has the extension '.jpg') These files are on average 750 KB. It is these files that are then put onto you main CD/DVD for copying onto your computer.
The resulting images will have a resolution of approx 2660 x 1820 pixels with a filesize varying between 500 KB and 1.0 MB. This will easily allow prints to be made up to A4 size. This would usually be satisfactory for most purposes. This is the resolution that I have used for my own collection of several thousand slides.
The Maths
Here's the maths. The 35mm film slide picture area is 36mm x 24mm. 36mm is 1.417 inches. Scanning at 2000dpi will produce 2834 dots so you end up with an image 2834 x 1890; 2834 x 1890 is equivalent to an image from a 5.4 megapixel digital camera. Your computer screen might have a resolution of 1024 x 768 pixels. Its maximum resolution is likely to be around 1280 x 1024 so your picture is about twice as big as your computer screen measuring linearly, or four times as big in area. Now what's the point of having a picture four times bigger than your computer screen? Well none at all really if all you want to do with it is look at it on a computer screen. But if ever you want to print the picture you'll need that extra detail. And if you want to trim the edges off a picture to home in on a particular part of it, then you have some leeway to do this. To see the printing capabilities of this size of image, there is a useful online megapixel calculator. In practice I find that the size of the picture in mounted slides is usually slightly less than 36mm x 24mm, so the actual filesizes and dimensions will be somewhat less than calculated here.
Professional customers who need to produce very large artwork and therefore require a higher resolution scan should approach a specialist company who regularly meet this requirement. A scan at 4000dpi produces TIFF files of 60MB or 120MB depending on colour depth chosen, and I do not offer this facility.
Also please note that I work with 35mm film only, not other formats such as 110, 120, 126, APS or medium format. 35mm film is 35mm wide in total including the perforations. It is also referred to as "135 film".
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What you receive
(Artwork may be different from those shown)
If you have opted to have TIFF files as well as the JPEG files, a second CD or DVD ('Archive') containing the same photos as uncompressed TIFF files, average size 14MB. |
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The Art and the Science of Sorting the Slides before you send them to me
It's not always clear which way round and which way up a slide should be, so I'm asking you to pack them in batches, the right way up and the viewing side to the front. Generally speaking the slide has one glossy side and one more matt side which has the emulsion on it. The glossy side is the side you view from. Some slides have nothing printed on them at all, but if they do, the glossy side may have a date and a number that appear upside down when you view the image. The matt side may have the manufacturer's logo on it. If you have them at the moment in carousels for inserting in your projector, please don't send the carousel. If you have them in heavy slideboxes it may be best to save weight in the post by taking them out of the box, bundling them in batches of say fifty and wrapping them in paper with sticky tape or elastic bands round them.
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Postage
If you use the local post office to send your slides to me, I would recommend using Royal Mail Registered Signed For or Next Day Special Delivery. With Special Delivery it is best to keep your parcel under 2 kilos. If it is between 2 and 4 kilos it is cheaper to split it into two separate parcels. Although the automatic compensation for loss is £500 the amount allowed would only be the very low cost of materials not the 'value to you' of your slides. If you wish to claim a higher amount you can pay extra for 'Consequential Loss'.
When I receive your package I shall send you an email immediately to let you know that it has arrived safely.
I shall use Royal Mail Recorded Signed For for the return carriage.
One favourite way of getting slides to me, if you don't live too far away, is to have a day out visiting Lytham which is certainly well worth a visit. Be sure to make a proper arrangement with me before travelling.
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A Word about Copyright
When you send your slides to me you are declaring that you own the copyright to those images. This means that you have actually taken them yourself or the owner has allowed you to send them to me. Please do not send any professionally produced transparencies that you have bought.
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Terms and conditions
- I can only accept orders from within the United Kingdom.
- I shall always take great care of your property. However I cannot be held responsible for any failure by the postal services. If you send a package to me that never arrives, you should make your own representation to the postal service.
- It is assumed that the customer holds the copyright of all photographs. I will process the slides as presented to me and cannot be held responsible for any breach of copyright.
- Your privacy is paramount. Your personal details will never be divulged to any third party. Likewise your photographs are kept strictly private and will not be made available to any third party.
- I shall give the slides a light and careful brushing prior to scanning, but I do not provide a cleaning or repair service. Proper cleaning, wet or dry, of photographic material is a specialist service that I do not provide. Also any slide that is falling apart cannot safely be put in the scanner. If I find the occasional slide that is coming apart I will remount it in a plastic frame but I can give no warranty for this extra work. (Basically I would not wish to disappoint a customer who may well not have noticed the odd bad slide-frame). But I will not undertake to do wholesale repairs on batches of slide-frames that have deteriorated.
- It can at times be almost impossible to be sure of the orientation of any particular slide. Once scanned, individual photographs can very easily be reoriented within your computer and if necessary I will send you instructions to do this.
- The slides will be scanned to the highest standard, but no warranty can be given regarding the appearance on any particular computer. Computer screens vary greatly in lightness and darkness etc. Also remember that if your original photo was not sharp, the scanned version will not be sharp either.
- If you send me very heavy wooden or metal slideboxes I shall ask you to pay any excess postage.
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