A: File types : what's the difference between a jpeg and a tiff?
Jpegs are great because the files are small. But beware there is a trade off, they are compressed files. To make the file smaller, jpegs remove pixels, ie. it will take most of the pixels out of a blue sky because it knows they are blue and simply replaces them when the file is opened again. This works well the first time a file is saved and reopened, but do it repeatedly and you're left with a jaggedy mess.
A: What are RAW and DNG files?
RAW files are unprocessed files. A jpeg file has been processed by the camera, the contrast, colour and sharpness have been decided by software in the camera. So when the file's opened in Photoshop, there's a limit to what can be done.RAW files are processed by the photographer after the shoot using special software. RAW, DNG and ACR files are like digital negatives.
A: CMYK and RGB?
RGB (red, green, blue) is the standard colour mode used by computer monitors, cameras and inkjet printers. Three colours are used to translate all the colours in a photograph. Litho printers use the CMYK colour mode instead : CMYK (cyan, magenta, yellow, black) gives printers more control, mainly because there's a true black (the 'k'). So books and magazines for example use CMYK. The files are larger than RBG files because they contain more information. CMYK conversions are taken from RGB files but it's a specialised field and success can vary for photo to photo.
A: What's DPI?
DPI stands for dots per inch : that's the amount of pixels in each square inch. Top quality is 300 dpi, web quality and screen resolution is 72 dpi. If you ask for a photograph at 300 dpi, you must also state what physical size. Otherwise its like asking for some top quality carpet but not telling the supplier how big the room is. Not to be confused with pixel dimensions.
A: Pixel dimensions?
Pixels are points of information. The more you have, the more detailed the photograph is (generally speaking). Many people are too obsessed with megapixels when buying a camera but this isn't the only thing you should be looking at. A camera might boast 10 megapixels but it doesn't always mean it's better than a 9 megapixel camera. The quality of the sensor and the lens in front of it are other factors that govern quality. It's like a car, the engine is one thing but you also have to look at the oil, the petrol, the electrical system etc to judge it's performance.
A: Why does my print look different to the computer screen?
Firstly, a computer screen is backlit so photographs do look brighter on screen than on print. Secondly, your printer and whatever software you're using are making colour adjustments which are out of your control. Getting prints to look like they do on computer screens is something that photographers spend a lot of time and money on.
A: What's white balance?
Different light sources give different colour casts. There's a nice logic to it, warm colours are red/yellow, cold colours are blue/green. Our brains neutralise these colour differences but cameras don't have a brain, they do as they are told.We need to be aware of it otherwise photographs come out with strange colours. So you understand, daylight at noon on a summer day is measured around 5000k, an overcast day more like 6000k and light from a tungsten light is 3400k. The lower the number, the warmer the light is.
A: What's noise and ISO?
Noise is a term to describe grain or blotchiness in a photo. It happens when a photograph is taken on a high speed setting.
ISO is the speed at which a camera sensor receives light (100 is low, 3200 high). If you raise the speed, you're asking the sensor to work extra hard, to record the light in as little time as possible. This creates electrical interference which creates noise in a photograph. Most sensors work best at 200 ISO, this speed creates the finest, smoothest photographs. In low light levels, you may need to raise the ISO but be aware that there's a trade off. Some cameras are better than others at keeping noise levels down at high speeds and sensors are getting better and better. It is possible to use filters to reduce the noise in Photoshop and shooting a RAW file helps because each channel of colour can be adjusted (and it's normally the red channel that contains noise).
A: What are colour profiles?
Colour profiles are tags attached to digital photographs and their reason to be is to control the colour representation of photographs. With the right colour management, a photograph is consistent and correctly depicted on a tv screen, a print, a computer monitor etc. To keep it simple : don't bin the profile the professional photographer supplied with the photo when you open it. It's probably 'Adobe 98', the most common profile. If you want to display the photo on the internet, convert it to an 'sRGB' profile if you have the software or ask your photographer to. If you want to get into colour profiling, buy a profiler (Color Munki or Eye One) for your monitor and recallibrate every month. Assigning the right colour profile in the print dialogue box is vital. For more information visit http://www.nativedigital.co.uk where you'll find a very useful support page.
A: What software should I be using?
To 'fiddle' with photos, the best is Adobe Photoshop. A simpler and cheaper alternative is Adobe Photoshop Elements. The differences are clear if you look at the price, £600 vs £60. For organising photographs, I use Bridge which is a component of Photoshop. Other photographers use Adobe Lightroom, Apple Aperture, Microsoft Expression Media (formally known as iView Media) and Picasa.There's a lot of software out there, I have listed the best.
A: Organising your photos?
Keep your photos organised, save versions when you make changes and keep the original intact : do this and you won't have any problems (providing you've backed it all up too).
Keep a folder of the originals and then create subfolders for files that you've worked on. It's time consuming and eats hard drive space but makes life easier in the long run.
Storing and backing up your photos is obviously vital too. You must back up on a second hard drive and it helps if that or another back up is somewhere else. Your office might burn down so if your one and only back up is in the same place, you're doomed frankly.
A: I want to buy a camera, what do you recommend?
This is a question I'm often asked. If you want to know which is the best professional camera, I can help. Otherwise, all I can do is offer advice about what to look out for. The manufacturers I like are Canon and Olympus. Don't be fooled by the 'megapixel' count, size isn't everything, it's what you do with it that counts and all the other cliches apply too ! It's the quality of the pixels that's important and that's governed by the quality of the chip in the sensor and the lens. A camera may have lots of bells and whistles but a second rate sensor. Also look out for shutter lag, some cameras take an age to respond to your finger pressing the button so you'll miss the moment. How long does the camera take to save the picture and allow you to take another one ? And servicing, do you have to send the camera to Hong Kong for a repair or are there UK repair centres ? Whatever you buy, it will do more than you need. Think about what aspects are important and buy the camera that meets your demands. Try not to touch the lens or let muck in, the best lens in the world will produce awful pictures if it's dirty. Like everything in this world, you get what you pay for. But whatever you buy now, you'll probably want to change it for a newer better one in less than five years and trust me, in five years there will be a much better version at a better price. Digital photography is still in it's infancy, professional photo journalists started using them in the early 1990s, they cost over £10,000 and today our phones do a better job. So in 2020, we'll all be able to afford the quality NASA pay millions for today.