Matters concerning the uploading of images to POL come up frequently in the forum. The web is a complicated thing so it’s no surprise that people struggle to understand how it functions; and most of us neither want nor need to know. However it was raining this afternoon and I had little better to do so I thought I would attempt to clarify one or two things arising out of recent posts. Some of the difficulties arise from the fact that us older folks are accustomed to seeing things on paper, and paper has a fixed size and does not vary and we all know how big A4 (for example) is. Size on the internet is not like that unfortunately. Monitors vary in size and can be set to display at various resolutions. iPads and ‘phones are different again. When you upload your photo you have no control whatsoever over what/how people are going to view it. It’s the algorithms that decide that. For this reason, resolution in the old-fashioned print-based sense (dots per inch) is irrelevant. Let’s start at the end with the way that the images are displayed on-screen. The screen you use has a resolution; it is ‘x’ pixels across and ‘y’ pixels down. It will of course be different between a mobile-‘phone screen and a desktop monitor screen. Also a desktop monitor may offer, in the display preferences, a choice of different resolutions, i.e. a different number of pixels for ‘x’ and ‘y’. Whichever of those options you choose once chosen it is set until you change it again for whatever reason. This is important because it means that the number of pixels the screen can display is fixed. Now, the way to view any image on-screen to get the best appreciation of the image is when each individual screen-pixel is displaying one image pixel. In the illustration, 1. is a jpeg of one of my life drawings. 2. Is an imagined close up of the screen around the area of the foot. You can see the individual pixels, each a different colour. In 3. the white grid I have superimposed represents the screen pixels and each of the image pixels is ‘contained’ within one of the grid boxes. That is, each of the screen pixels is displaying one of the image pixels. In 4. we are seeing the small 2x2 pixel area outlined in black. Each pixel has its own colour. So far so good. Now let’s think about the image itself for a while. When you save the photograph of your artwork as a jpeg, that image-file will have a fixed number of pixels. Unless you have access to Photoshop or a similar photo-editing software, you cannot change these pixel dimensions. Most people uploading their artwork to POL are in just this position I believe. It helps then, to understand just a little of what is happening. Suppose the pixel dimensions of the jpeg do not accurately coincide with the pixel grid of the screen. You can imagine something like 5. happening, where some of the screen-grid pixels ‘overlap’ more than one of the jpeg pixels. A pixel can only be one colour, so in 5. all but the top-left pixel of the four there is a problem. That’s where the algorithms come in again and they determine what colour those pixels should be by doing sum really hard sums. Usually it will be an average of the colours. This has an affect not only on the colour or tonal values but also on the resolution in terms of detail. If the dark-brown pixels in my crude four-pixel example are also defining an edge-detail then that averaging will affect that edge-detail. That said the algorithms are sophisticated enough to deal with this in most circumstances. I don’t use my iPad to edit pictures because I’m lucky enough to have access to Photoshop, but I’ve just had a look at the editing capabilities and it’s a little awkward to use but is not at all bad (I have no experience but can only assume that other iPad-type devices are similar). My suggestion for artwork, would be to ignore the flashy stuff such as ‘Vivid’, ‘Dramatic’ etc. and concentrate on the brightness, contrast, shadows and highlights settings. But be careful, it’s easy to overdo it. Ideally the highlights should be adjusted so that lightest area of the image is still showing detail. Similarly for the shadows; the darkest area should still hold some detail otherwise the shadow areas may end up looking like cut-outs. There is no information on the POL site as to the ideal image file for the site and all I can say in this respect is that I have always edited the image and saved it as a jpeg, adjusting the quality slider for a file-size of around 2 megabytes. This has worked fine on all of the three devices I use (laptop, iPad, iPhone), for a variety of paintings and drawings of different sizes. Unfortunately the iPad doesn’t give you the option to control the file-size. It’s my guess that a great many POL artists photograph their artwork on a ‘phone or iPad and, on the whole, they achieve much better results than I ever did. I have in the past used the iPad to photograph paintings but the photos were then edited in Photoshop. The biggest difficulty I experienced was in getting the image straight. The iPad lens is of such short focal-length that very small movements can have dramatic effects on the end result. Other than constructing some rig in which the iPad can be kept exactly parallel to the artwork, I don’t have an answer to this. Although I cannot offer any magic solutions, I hope that my rather crude examples here at least go so way to explaining what the difficulties are.