Subtitles of the Movie

Now let's take a look at some practical demonstrations of all this theory I've been throwing at you so you can understand exactly what happens when an image is converted into JPEG and thusly compressed to a smaller file size. We'll take a look at the copies of this image of Laura and we have two TIFF images and one JPEG. Now the TIFF image on the right is converted to a TIFF from a raw file because of the simple fact that Photoshop Elements will not open the raw file, so I have converted it, but I've done absolutely nothing to it to demonstrate to you how the image looks directly off the sensor. Now there is a little bit of a green tint to it, but be aware that you know, raw files always need to be adjusted. Yes, the image is exactly as it came through the lens and was captured by the sensor and converted by the AD Converter, but they always need something done to them to make them look their very, very best, and in this case we had a slight green tint. Now the image in the middle has also had nothing done to it whatsoever in the conversion process except white balance. Now it looks cool, it is absolutely very, very cool, and we're going to warm this up later on in the process, but at least we got rid of the green tint. Now the image on the left is the JPEG and what I want to do is let's zoom in on these images to get to pixel level so that I can show you exactly what happens when an image is converted into JPEG and also why you should never print a JPEG and I think it'll become glaringly obvious to you. And again, we're going to zoom in on this image to 700 percent, and that's indicated in the top bar of the image as we click on the magnifying glass out of the Toolbar. There we have it, okay. Let's look at the raw file and we can see here that the detail information is very clear. We've got a lot of contrast between adjoining pixels. You've got pixels that are very dark right next to pixels that are gray, bright; there's a lot of variation in the individual pixel shading in this detail area. Now down here where the color is pretty much smooth and the same, you still have individual pixels that are visible which you know, when the image is zoomed out to full size results in an image that has pop, it has sharpness, it has presence, vividness that you would always expect from a raw file. Now here's the TIFF image that's been color-adjusted, white balanced, and you have the same detail, exactly the same detail pattern here as you do here, so no difference whatsoever in terms of the pixel contrast, the contrast between adjoining pixels. But if we look at the JPEG image, we can see quite a difference. It is modeled, smoothed out, blurred if you will, and the reason for that is because the JPEG algorithm, the way that it achieves the result of reducing the file size is that it takes detail information and color information between adjoining pixels and it throws it out. It replaces it with colors and pixels that it thinks should go in there to fool the eye when the image is enlarged. But nonetheless this is a degraded image. This is an image that has been damaged for the sake of file size. Also note that it's been changed to an 8-bit image, which means there is substantially less color information overall in the image and you'll notice that TIFF image remains at 16-bit, which means that it captures all of the color information off the sensor, which the sensor and the AD converter are capturing the light here at 12-bit. So, not only do we have image detail that's superior over the JPEG we have more color information, which gives the image more presence and more pop, and the JPEG just simply does not have the oomph to give you a nice quality print. So, don't print JPEGs, print only TIFFs and as we go forward that's going to be our mantra, is when we talk about JPEGs Ð for the Internet; we talk about TIFFs Ð those are going to be for printing.