Slides for gobo projectors
Slides for nightclubs, shows and gobo spot projectors
If you are using regular carousel type projectors then all you need to do is load up the magazine with slides. If you are using something like an Optikinetics Solar or GoboShow then you will find a specification of ’50mm slide’. This is just a regular 35mm slide! Please ask you supplier or hirer whether they recommend plastic or glass mounted slides – if you don’t know then choose glass mounted by default.
Preparing digital files for gobo slides
Design
Most images used for this application will be logos – the idea being to ‘float ‘ the logo across wall, floors or screens. This requires a different way of working to normal print media.
35mm slides have a dimension ratio of 3:2 – we output slides at 4096×2732 pixels (exactly that and always that) so if you are creating artwork in Photoshop then this is the resolution you need to use for best quality – dpi or ppi are irrelevant, it is pixels that count!
Start with a black background and work in RGB – converting from CMYK will turn black to very dark grey. The logo can be placed on this background – should the logo have black elements and merge with the background then you will either have to use a ‘reversed out’ logo or use some other device such as outlining in white or use something like a glow.
Maximise the logo size to pretty much the edge of the artwork – there is no need to leave space, it will just make your projected image smaller.
There is no limitation to the number of colours you use – from a plain black and white image to a full colour rainbow, makes no odds to us!
Incidentally, Illustrator, EPS and PDF files are fine too.
Compression
If you are sending your images on CD then by all means save as TIFF or PSD. If you are sending images over the wires then please use JPEG (even if you are using FTP and Broadband there is no point hogging valuable bandwidth, and anyway life is too short). A 4096×2732 pixel image is about 32Mb – save as JPEG using ‘maximum’ or ‘high’ quality settings (8-10) that will result in files a tenth of the size or less and give NO visible compression artifacts on your final slides. Remember that you are sharing bandwidth with your neighbours – be considerate!
Longevity
Spot projectors have incredibly powerful lamps. All this light is focussed on the small 36mm x 24mm slide before being projected onto a wall. This means there is a lot of heat too. If your projector has poor forced ventilation then the slides will burn and over time the light will fade the dyes in the slide. Luckily, most applications of logo projection are short-lived so this shouldn’t matter but it may well be prudent to order a couple of slides just in case of disaster. The use of 35mm slides in gobo projectors is meant to be practical, speedy and cost-effective. A full colour slide will cost just £4. If you want something with a long life span then you need a special dichroic glass slide that will cost you something like £260 per gobo. Looked on this way even a pile of 35mm slides ready to be chucked away after a couple of days use is still very cost effective.
Colour management
If your head spins at the concept of colour management don’t want to worry, your images are going to look fine so skip to the next paragraph.
If you DO use colour management, that is great too. We accept files with any embedded profile. Remember that colour profiles are used to adjust colour throughout the workflow, from image creation to final output with the aim of producing consistent, expected and repeatable colour regardless of the device used relative to the potential of the final output media. In other words what you see on screen is what you should get on film, within the limitations of the media. However, do not use CMYK in your workflow at all or else you will have to be shot – this is only appropriate for litho print and will seriously degrade the quality of your images.
Simple solution – most digital cameras and inkjet printers are calibrated to sRGB – make sure you screen is too and Bobs your Uncle – simple, foolproof colour management.
Summary
Use a black background to the artwork
Work in RGB
Work close to the edges, make full use of the working area
We output at 4096×2732 pixels – dpi or ppi are irrelevant, it is pixels that count!
35mm slides have a dimension ratio of 3:2
Save as high quality (level 10) JPEG
Ask first – if you are not sure send a quick email and we will advise
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More information on how to prepare files for gobos and a bit of insight on why things don’t work as expected!
OK, here is our company logo. Simple, bold design – should project well!
But make this into a slide as-is and project onto a darkened venue wall or floor and you end up with a bright white rectangle – not the logo you hoped would be ‘floating’ there.
OK, so you have read the notes above and prepared your artwork properly with a black background. Black is the absence of light and therefore nothing will be seen on the wall. But wait – that’s wrong – the black part of the logo can’t be seen!
Right, we need to fix that. The key phrase is ‘reversed out’. That is to say your logo needs to be a negative, so black becomes white..
Or you could outline the black text or put a glow round it – whatever you do, you want to retain a perfectly black background.
Great! All sorted – projected logo now works well in a darkened room. But what if you aren’t projecting onto a light coloured wall. What if it is a red carpet?
Ooops, that doesn’t work!
Nope, doesn’t work very well onto a blue carpet either!
So, the moral is – start with a black background. If you don’t know the colour of the surface being projected onto then stick with a reveresed out white on black image. This may need some thinking about if the logo is complex and if the designer never gave any thought to situations other than printing onto white paper – very common! And bear in mind that a company Pantone colour doesn’t have a hope of being that colour when projected – projectors have a very yellow light source and goodness only knows what colour surface is being projected onto! Keep thing simple – white on black always works.
Or you could consider using some greys or outlining or glows to add a bit of interest.