Thursday, 6 December 2012

CONT. PHOTOSHOP WORKSHOP

Automate Options can allow Photoshop to do work for you, such as building panoramas or straightening out images.Today I learnt to use the Median tool. 

Median Filter:

There are four filters in Photoshop that are designed to reduce noise (and one filter to add noise). One of the most useful of these filters is the Median filter. The Median filter looks at pixels, within a specified radius, and blends the luminance of the pixels. The filter does this by calculating the median value (a type of average) of the pixels within the radius and assigning that value to the center pixel. In a sense, it averages out the noise. -- ronbigelow

Script > Load Files from Stack


Browse files to upload images. 
By selecting the 'smart object' option allows the images to be edited afterwards also, in the same way as vector images.

Adding multiple photos to one 'stack' to edit collectively, or by using the automate option as seen above. A series of 128 photos have been added together to one 'stack'.

 Aligning Images - Straighten out photos if not taken straight, for example.

Here 128 images have been uploaded to Photoshop under one file as seen above. The images are shown in the 'layers' panel, and will be in one layer when all images have been uploaded.

The photos have been added to one smart layer as seen on the right in the layer panel.

 
By selecting Layer > Stack Mode > Smart Objects >  Median, the people will be removed from the image by removing movement which has been captured.

As you can see the image has been transformed into a perfect scenic photograph. such as those of cities which appear desolate, such as New York.

By selecting a photo with a much more vivid sky is also something else I can add into the image, to enhance the visuals.

By using the Quick Selection Tool which is highlighted on the left, I am able to select the sky I would like to keep, and press Select > Inverse and then delete which will leave the finished photo as shown below.


Completed Image using Median tool.


File Types:

Digital Image File Types Explained

Source:  http://www.wfu.edu/~matthews/misc/graphics/formats/formats.html

JPG, GIF, TIFF, PNG, BMP. What are they, and how do you choose? These and many other file types are used to encode digital images. The choices are simpler than you might think.
Part of the reason for the plethora of file types is the need for compression. Image files can be quite large, and larger file types mean more disk usage and slower downloads. Compression is a term used to describe ways of cutting the size of the file. Compression schemes can by lossy or lossless.
Another reason for the many file types is that images differ in the number of colors they contain. If an image has few colors, a file type can be designed to exploit this as a way of reducing file size.

Lossy vs. Lossless compression

You will often hear the terms "lossy" and "lossless" compression. A lossless compression algorithm discards no information. It looks for more efficient ways to represent an image, while making no compromises in accuracy. In contrast, lossy algorithms accept some degradation in the image in order to achieve smaller file size.
A lossless algorithm might, for example, look for a recurring pattern in the file, and replace each occurrence with a short abbreviation, thereby cutting the file size. In contrast, a lossy algorithm might store color information at a lower resolution than the image itself, since the eye is not so sensitive to changes in color of a small distance.

JPEGs can be lower in quality due to compression of the image (LOSSY)
TIFFS should not be used on the web, but should be printed. (LOSSLESS when finished, whilst in progress save it as PSD).

The file types

TIFF is, in principle, a very flexible format that can be lossless or lossy. The details of the image storage algorithm are included as part of the file. In practice, TIFF is used almost exclusively as a lossless image storage format that uses no compression at all. Most graphics programs that use TIFF do not compression. Consequently, file sizes are quite big. (Sometimes a lossless compression algorithm called LZW is used, but it is not universally supported.)

PNG is also a lossless storage format. However, in contrast with common TIFF usage, it looks for patterns in the image that it can use to compress file size. The compression is exactly reversible, so the image is recovered exactly.

GIF creates a table of up to 256 colors from a pool of 16 million. If the image has fewer than 256 colors, GIF can render the image exactly. When the image contains many colors, software that creates the GIF uses any of several algorithms to approximate the colors in the image with the limited palette of 256 colors available. Better algorithms search the image to find an optimum set of 256 colors. Sometimes GIF uses the nearest color to represent each pixel, and sometimes it uses "error diffusion" to adjust the color of nearby pixels to correct for the error in each pixel.
GIF achieves compression in two ways. First, it reduces the number of colors of color-rich images, thereby reducing the number of bits needed per pixel, as just described. Second, it replaces commonly occurring patterns (especially large areas of uniform color) with a short abbreviation: instead of storing "white, white, white, white, white," it stores "5 white."
Thus, GIF is "lossless" only for images with 256 colors or less. For a rich, true color image, GIF may "lose" 99.998% of the colors.

JPG is optimized for photographs and similar continuous tone images that contain many, many colors. It can achieve astounding compression ratios even while maintaining very high image quality. GIF compression is unkind to such images. JPG works by analyzing images and discarding kinds of information that the eye is least likely to notice. It stores information as 24 bit color. Important: the degree of compression of JPG is adjustable. At moderate compression levels of photographic images, it is very difficult for the eye to discern any difference from the original, even at extreme magnification. Compression factors of more than 20 are often quite acceptable. Better graphics programs, such as Paint Shop Pro and Photoshop, allow you to view the image quality and file size as a function of compression level, so that you can conveniently choose the balance between quality and file size. 

RAW is an image output option available on some digital cameras. Though lossless, it is a factor of three of four smaller than TIFF files of the same image. The disadvantage is that there is a different RAW format for each manufacturer, and so you may have to use the manufacturer's software to view the images. (Some graphics applications can read some manufacturer's RAW formats.) 

BMP is an uncompressed proprietary format invented by Microsoft. There is really no reason to ever use this format.

PSD, PSP, etc. , are proprietary formats used by graphics programs. Photoshop's files have the PSD extension, while Paint Shop Pro files use PSP. These are the preferred working formats as you edit images in the software, because only the proprietary formats retain all the editing power of the programs. These packages use layers, for example, to build complex images, and layer information may be lost in the nonproprietary formats such as TIFF and JPG. However, be sure to save your end result as a standard TIFF or JPG, or you may not be able to view it in a few years when your software has changed.

Currently, GIF and JPG are the formats used for nearly all web images. PNG is supported by most of the latest generation browsers. TIFF is not widely supported by web browsers, and should be avoided for web use. PNG does everything GIF does, and better, so expect to see PNG replace GIF in the future. PNG will not replace JPG, since JPG is capable of much greater compression of photographic images, even when set for quite minimal loss of quality.

PDF Allows for multiple pages to be saved and sent at once, all in one file. PDF's can be opened on any computer, even if they do not have Photoshop etc. (Portable Digital Format).

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