Film Positives

We pride ourselves on being one of the last suppliers in the country of traditional true photographic film positives. Not only that, but we can produce these positives to a massive size of 4500 x 1600mm in one piece.

This article is not meant to confuse or put off anyone asking for films from us, and you should know that our friendly staff are always happy to make any alterations to you work to ensure that you get the best results possible (normally at no extra cost), but there are a few things you may want to consider when supplying artwork files to us for film.

The first thing to know is that we do not use an inkjet to produce the films, but an imagesetter. This means that a lot of what you have been taught either by colleges or online will not be completely correct. This is because an imagesetter is built for the sole purpose of producing ultra high resolution film positives and separations on photographic film, resulting in a perfectly sharp and (importantly) dense images.


Rule #1: Do not use RGB

People are often told that their files should be made in RGB so that the black parts of the image will be as dense as possible on the film acetate.

While this may be true if you were printing on a colour printer, this is not the case when the film is being output on an imagesetter. The photographic film in an imagesetter is exposed with a laser and then developed in a film processor, which produces a very dense image which allows no light at all to pass through. Therefore, files should be supplied as either greyscale, or CMYK.

RGB has its place, and that is colour digital prints – not film positives.


Rule #2: Do not create your own halftone in Photoshop

Although Photoshop is capable of creating a halftone, this should be avoided unless you want a particular type of effect (like diffusion dither for example).

The RIP will create a much better halftone, and at the native resolution of the imagesetter (over 3500 dpi) which is totally impractical to do in a program like Photoshop. This is especially true if you need separated CMYK films, the RIP will create the halftone at the correct angles to produce a set of 4 colour process films with no moiré clash.

If you know what halftone you require, tell us when you send us the file. Alternatively, we can advise you – based on the printing process you will be using the films for.


Rule #3: Avoid using Photoshop for text or other line drawings.

Photoshop, as its name suggests, is for photos (or other pixel based images). It is very good at manipulating pixels, but when it comes to producing the sort of crisp edge and solid colour that a piece of text or a logo needs – pixels do not produce the best result (unless they are created at unnecessarily high resolution).

Vector text compared to pixel text

A vector based drawing program like Illustrator will always give a better result for text and illustrations. If photos are needed in your design, then they can always be placed in the document as a link and masked with clipping paths to a shape if required. Not only will the resulting image look much better, this will nearly always create a smaller file. Meaning you can archive it more efficiently and send it to us quicker.

There are obviously many effects produced in photo editing software like Photoshop that simply cannot be achieved in drawing programs like Illustrator, and that’s fine – but just try and use the right tools for the right job.


Rule #4: Layers are not the same as spot colours

Sometimes you may want to create one or more spot colours in your print job – this is very common, especially in screenprinting. What you need to be aware of though, is that creating multiple layers in Illustrator or Photoshop does not affect the number of individual film separations. Layers are simply intended to aid you creating and editing your image.

Spot colour in Illustrator

If you want to create spot colours in Illustrator, simply add the colour to your swatch pallet and make sure that it is marked as a spot colour. You can check this by double clicking the colour square in your swatches list and then ensuring that “Spot Color” is selected from the “Color Type” drop down menu. Anything in the document that uses this colour will now be output as a separate film.
When the films are output, they will automatically be labelled with the name of the swatch, so you can call it whatever you like.

Photoshop is a bit more complicated. It is always very tempting to add layers when trying to create additional separations, but in fact it is Channels that you need to add.

Adding a Spot Channel

To start with, your file should be either greyscale or CMYK (but you already knew that after reading “rule #1” above). You can then add a spot channel from the Channels pallet by clicking on the symbol and choosing “New Spot Channel” from the pull down menu.

Spot Channel settings

You will then be able to choose a name for the separation and select a suitable colour for displaying it on your screen (by clicking the coloured square under “Ink Characteristics”. There is also the option of choosing the “solidity” – this has absolutely no effect on the output film, but merely alters how the spot colour will display on your screen.

You can then get to work creating the artwork that will appear on this separation. Because this spot channel represents a single film, you can basically do anything with it that you would normally do to a greyscale. Including copying, pasting, retouching and adjustments.

When you are happy with the file, you will find that your use of spot channels will restrict the format options of your saved file. What you should select is “Photoshop DCS 2.0”, then in the following dialogue box you should select “Preview: TIFF (8 bits/pixel)”, “DCS: Single File with Color Composite (72 pixel/inch)” and “Encoding: Binary”. The rest of the options should be left unchecked.


This all may seem a little daunting, and a lot to take in. But remember, we are here to help, and won’t charge any extra to do all this for you unless there is an extraordinary amount of time that we need to spend on your files.

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