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Advice on Image Quality
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| First, what does RGB mean? | ||
| Images can be in different colour modes: RGB, CMYK, CIE LAB etc. A picture taken on a digital camera or scanned on a scanner will be RGB (unless the scanner has been deliberately set to CMYK). RGB is the colour setting used for the web (it stands for Red, Green, Blue which is how computer screens normally create colour). For commercial print, RGB images need to be changed into CMYK (cyan, magenta, yellow, black or 'key'), which are the inks used for full colour printing on a printing press. Only RGB shows on a web page and so if the image is not RGB, the recipient won't be able to see it on or download it from the site on which the Press Release Submission form places it on upload. Unless you are professionally involved in graphics, you can be pretty certain your images (especially if taken straight off a digital camera) are in RGB and so you need to do nothing about colour: just upload it. If you know the image is not in RGB, you need to change it to RGB. Advice can be sought from Chris Whitby if in doubt. |
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| File Format | ||
| The Upload form is designed primarily for jpg and gif images. If the image is the wrong filetype the upload will fail. Jpg (sometimes jpeg) is a compressed form of image, much used on the web and for email interchange. Being compressed, a jpg is a smaller filesize than a tif or other type of uncompressed file; thus a 1.8MB jpg may decompress to, say, 15MB as a tif or tiff file (your computer sorts out the decompression). Digital cameras usually store images as jpg files. Gif is also a compressed form. Gifs are more efficient for things like logos where there are large areas of flat colour. Jpgs are best for photos (gifs are less good with graduated colour or images where nearly every pixel is a different colour). |
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| Keeping Quality | ||
| Digital cameras usually save at 72 dpi (dots per inch) or sometimes 180 dpi. Commercial print operates at 300 dpi. Therefore a commercially printed image (300 dpi) only keeps the original quality by rendering a 72 dpi image at approx 1/4 size (72/300) or a 180 dpi image at just over half size (180/300). Thus a 400mm x 300mm photo at 72dpi will be used in commercial print at no more than 100mm x 75mm. If you scan a photo print, set the scanner to 300 dpi to get best quality. If you are taking digital camera pictures for use with a press release, set your camera to record the highest quality (largest filesize) picture it can - this ensures the maximum number of pixels are used. This will mean fewer pictures on the memory card, but the quality and potential printing size will be better. If you use the 'lowest quality/most pictures on the memory card' setting on your camera, there is a danger that the image you send will be unusable. A 320 x 240 pixel setting on the camera (about lowest quality likely to be available) makes an image approx. 112mm x 85mm at 72 dpi, but changed for 300dpi printing (i.e. 1/4 size), it will print at 28mm x 21mm which is barely larger than a postage stamp! Look at your images for lightness/darkness, contrast (good or 'flat'?), colour saturation (strong colours or faded) and any colour cast (overall too blue or too yellow?). If you know how to improve the images before sending, do so. If not, let the publication sort this out (you can add a note at end of press release asking them to do so, as you are an amateur and they are professional in this field). Digital cameras are very good in strong sunlight outside, but struggle with indoor shots, which are often very grainy and often have a yellow colour cast. If you know you are shooting under normal light bulbs, see if your camera has a 'white balance' setting for tungsten lighting as this can help prevent the yellow colour cast created by this lighting. If in doubt, leave on 'automatic white balance' setting, especially if using flash. When resaving an altered image, save at the maximum quality your image program will allow. Professional programs allow settings for jpgs on a quality range of 1-12 or sometimes 1-10. Choose the largest number as this is higher quality. If the resulting file is more than 2.5MB, choose a lower setting, but don't go below 7. Remember that each time you save a jpg, it loses quality. Don't continually save a jpg as a jpg, as with each resave, the image deteriorates. Finally, NEVER NEVER send a photo placed inside a Word document. Our program won't cope with it, and even if sending the Word document separately by email, it's still something NOT to do. The reason is that Word automatically downgrades any image placed into it as a low quality 'cover' file (something Microsoft does not explain). It may print OK on your desktop inkjet printer (they are incredibly forgiving as the ink dots spread on the paper), but it will not look good when commercally printed at 300dpi. Word also has no export image facility, so recipients can only copy/paste the image into another program and Word sometimes does strange things with colours when you do this. ALWAYS send images as separate attachments. Your photo may be what sells the story. It's worth assessing your choices so you send the best image at the best quality. |
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