SCANNING, RESOLUTION, AND FILE FORMATS

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1 Resolution SCANNING, RESOLUTION, AND FILE FORMATS We will discuss the use of resolution as it pertains to printing, internet/screen display, and resizing iamges. WHAT IS A PIXEL? PIXEL stands for: PICture ELement. It is a single building block of detail in a raster image. Every Pixel has a: Size, Color, Location. This is what takes up the majority of our digital photo s size in memory (KB, MB, GB). A blank white 8 x 10 x 300PPI RGB canvas in Photoshop takes up 20.6MB, the same amount of memory it would take to have a full color image displayed. Canvas space isn t free. RASTER VS. VECTOR Photoshop is a raster graphic application. It uses square pixels to represent detail, this works especially well for photography. Some other applications like Illustrator use vectors to render their graphics. Vectors are math coordinates between nodes, this works well for logos and icons. Raster images are distorted when enlargements are made, this is known as interpolation. Vectors can be scaled without distortion, and are resolution independent. RASTER GRAPHIC VECTOR GRAPHIC RESOLUTION Resolution is the measurement of detail in a raster file. It is generally measured by how many pixels per inch (PPI) are in an image ie; 240PPI. The resolution of 300PPI is ideal for printed images, *at appropriate viewing distance. This is because that is the amount of pixels per inch needed to trick our eyes into seeing a continuous tone image, and not being able to distinguish individual pixels. Web sites display 72PPI and this measurement is considered low for photographic printing, but appropriate for web pages. Pixels in low resolution images are obviously noticeable to the eye on printed images. HIGH RESOLUTION LOW RESOLUTION RESAMPLING Resampling is the digital process of changing the resolution or dimensions (size in inches) of digital imagery by analyzing and sampling the original data. This process uses different algorithms (a specific set of math instructions) to analyze and invent the new detail, based on the original. Photoshop is much better at hiding the pixels after resampling an image, and instead of making it look pixilated (visible pixels) it looks blurry. It does this because of the algorithms used, and the occurance that our eyes are much more accepting of blurry images over pixilated ones. Doubling the resolution of a file will quadruple the memory it takes up on your Hard Drive, because the pixels have both an X and Y axis. ORIGINAL RESAMPLED WHY IT MATTERS This is the reason that we can t take small images from cell phones, and the internet and blow them up to the size of a poster, print them and have them be sharp, crisp detail. Don t be fooled by TV shows special effects like blurry surveillance photos blown up and enhanced making people s faces identifiable. These are fake computer effects, done for dramatization. If it were true, we could all take google thumbnail images and blow them up to be wall sized posters, and they d look great, we know that this isn t the case.

2 Resolution t t t t t t t RESIZING AND RESAMPLING Under the Image/Imagesize menu we can see our total pixels, width, height, and resolution. It will allow us to make any adjustment we want (like giving our file 30000PPI and making a 200GB file, which is never a good idea) however it is very important you understand what it is doing to your image. Photoshop assumes you are the expert and that you know what you are doing. It does not give any indication that what you re trying to do might not be the best idea. BASE SETTING: Here we see the original Image/Image Size dialog box for the image we want to resize. RESAMPLE UNCHECKED: With Resample unchecked, it locks width, height, and resolution together. Now we can tell it the resolution we need, and it will resize the image appropriately. t t ORIGINAL These are the settings from a file brought into photoshop right off of a digital camera. They are based off of setting on the camera when it was shot. If this was your camera, you would have control over these, and need to know that you cannot easily change the resolution of a photo after it is shot. When in doubt, always shoot the maximum image resolution your camera can handle. You might never get another opportunity to take the image again, make it count. Never rely on photoshop to clean it up later. It can t always save us from hastily made mistakes. BEST METHOD The reason this is the preferred method of resizing your image is that it does not add any pixels, it just resizes the existing ones. Therefore no soft detail is added, however you trade size in inches for a higher resolution (PPI). The higher the resolution you need, the smaller the original becomes, it s a trade off. You can t have your cake and eat it too. Note the pixel totals for Width, Height, and Pixel Dimensions file size. The file retains the same amount of memory and pixels, no memory or pixels were added/deleted. It just reconfigured existing detail. RESAMPLE CHECKED: With Resample checked, we can determine the width, height, and resolution independently. This allows resampling, which invents detail and does not make the image appear any clearer. Trust me. AVOID IF POSSIBLE The reason this method should be avoided is that it invents the new detail based on an algorithm, and massive amounts of memory are added to our file. This new detail will never be better than the detail in the original, and will just look fuzzy to try to hide itself. However sometimes this method cannot be avoided, and must be used. There are advanced tricks to limit the amount of fuzziness. Note the pixel totals for Width, Height, and Pixel Dimensions file size. The memory in the parenthesis was the file size of the original. The new file grew in memory by 8X, that memory comes from the resampled invented detail. WHY IT MATTERS Inventing detail and hoping no one will notice should not be an acceptable alternative to understanding the limitations of the camera you own, or educating the people you work with to try to get you high resolution images when available. If someone says Get that picture from my web site, you should know that you are most likely going to have an image that is both compressed, low resolution, and there is not much you can do to fix it with photoshop to ever get it to print well.

3 File Formats FORMAT COMPRESSION ADVANTAGE DISADVANTAGE PSD Layers are compressed losslessly. Preserves image layers, adjustment layers, all paths, etc. Usually cross platform. Can be any color mode, although some color modes do not allow the use of layers. TIFF LZW compression optional. LZW is lossless, but it slows down printing. LZW works best on large areas of solid color. Avoid other types of compression. TIFF files are the best format to use for flattened graphics that are raster only. Widely recognized format. High resolution TIFFs are ideal for photographic printing. EPS No compression. Vector EPS files are scalable and relatively small. Raster EPS files can have clipping paths. Good for printing vectors. Must be converted for web use. GIF JPEG CAMERA RAW Compressed format. GIF format is best for solid color illustrations. Compression can be lossless or lossy. Compressed format. Lossy, but can be adjusted to less compression which creates a bigger file with less garbling of the image. Usually not compressed, but RAW formats are proprietary, so it is possible that some company could create a version of RAW that is compressed. Good for illustrations using solid colors, type on solid backgrounds, etc. Works for the web, but not for print. Can be used for animations. Best for photographic (continuous tone) images on the web. Will compress RGB or CMYK images, but CMYK images won t work on the web. Adjustable compression. RAW files contain uncorrected sensor data from a digital camera. Automatic correction is inferior to skilled correction. Holds a massive amount of sensor information. Photoshop files should be saved as another format for use in print or multimedia (web). Files can be very large if they contain many layers. Relatively large files. Can t be used in browsers. LZW compression not ideal for print. Photoshop now allows one to save layers and use JPEG compression in TIFF files. It shouldn t. Previews can look chunky in Quark, ID and Illustrator. Can t be used in browsers. Confusing, since eps files can be vector, raster or both. Requires the use of indexed color, limited to 256 colors. Can t be used for print. Will cause artifacts as a side-effect of compression. Not ideal for print. Massively compressed images cannot later be uncompressed. Flattens your Layers in Photoshop. Must be interpreted, or post processed, in order to be useful(this is a plus and a minus). Very large files. THESE ARE JUST COMMON FILE FORMATS There are literally hundreds of file formats out there, but these are the ones you will be dealing with the most if you are using photoshop and working with images. WHY IT MATTERS There are many reasons you should be aware of what the listed file formats do to your file. If you ve ever saved your picture as a JPEG and lost all of your layers, tried to post a TIFF to your web site, or have been unable to open a Camera Raw file, then you know what I am talking about. RECOMMENDATIONS I suggest the following Shoot in Camera Raw on your Digital Camera if possible, however, not all cameras have this option. Shoot in JPEG with maximum quality/resolution if Camera Raw isn t available on your camera, however, do NOT re-save it in Photoshop as a JPEG and further compress your image if you ever want to print it. File/Save As to a PSD or TIFF for adjusting/printing. Use TIFFs and PSDs for high resolution photo printing. Use High, or Maximum Quality compressed JPEGs for posting images onto the web.

4 Project 1 PROJECT 1: FILE FORMATS AND RESOLUTION POINTS POSSIBLE: 5 WHAT YOU SHOULD LEARN Width, height, and resolution are defined when taking a picture with your digital camera, or when scanning a pre-existing image. It will determine what we are able to do with our image after it has been taken or digitized. It is not easily re definable later without trade offs. File formats play an important role in how our images are handled by image editing applications, there are permanent consequences if we aren t paying attention to the file format we choose. After a.jpg image is compressed you cannot undo this compression. If it was set to a low compression setting and artifacting occurred, there is no way to get rid of it from that file. Reinforcement of tools, shortcuts, and basic navigation skills while we re working on an image. Uploading files via FTP on the class website. STEP 1 Download the project_1_files folder from the class website. Open the file it8_target_72.psd. Zoom the image using the Zoom Tool(z) to zoom in to 100%. Look at the detail in the faces and the type, now zoom in to 300%. Now open up the file it8_target_300.psd and do the same. The native 300ppi image should look much better, and hold much more detail than the 72ppi file. Close the 300ppi file. STEP 2 In the 72ppi Image, go to the Image/Image Size drop down menu. Make sure that Constrain Proportions is CHECKED, and Resample Image is UNCHECKED. Changing the resolution now should also change the width and height, since they are all locked together. STEP 3 Change the resolution to 300ppi and observe the width and height measurements. You have traded image size for a higher resoution. This is the correct way to resize an image s resolution without loss of detail. OK the image size box. STEP 4 Go to the File/Save As drop down menu. Change the name to lastname_project_1_resize.psd Leave the format as Photoshop, and choose a place on your hard drive where you are going to save files to that you will upload via ftp to the class website. Click Save, and agree to any file format options such as Maximize Compatibility. Close the file. STEP 5 Reopen the original it8_target_72.psd file. In the 72ppi Image, go to the Image/Image Size drop down menu. Make sure that Constrain Proportions is CHECKED, but this time Resample Image is CHECKED also. At the bottom of the image size box, make sure it is set for bicubic, this is the resample algorithm we want. Now, changing the resolution now should NOT effect the width and height measurements. Change the Resolution to 300ppi. Note what happened to the Pixel Dimensions file size. We have invented 6 times the original detail. OK the image size box.

5 Project 1 native 72ppi 72 resample to 300 native 300ppi STEP 6 Look at the detail in the faces and in the type. Does it look as good as the original 300ppi image did? Notice that it doesn t look pixelated, but blurry, this is because of the bicubic algorithm. Other algorithms will interpret the detail differently, but that is a bit more advanced of a topic. STEP 7 Go to the File/Save As drop down menu. Change the name to lastname_project_1_resample.psd Leave the format as Photoshop, and choose a place on your hard drive where you are going to save files to that you will upload via ftp to the class website. Click Save, and agree to any file format options such as Maximize Compatibility. Close the file. PRE COMPRESSION STEP 8 Open the file azureus_72_small.tif. Go to the File/Save As drop down menu. Change the name to lastname_project1_compression Change the format to JPEG, and choose a place on your hard drive where you are going to save files to that you will upload via ftp to the class website. Click Save. In the JPEG Options box, change the quality to 0. Notice the lossy compression, This is how JPEG files manage to be so small. They throw out image detail, and group colors together, making for a very choppy, pixelated image when heavily compressed.close the file. POST COMPRESSION STEP 9 We are now going to upload our 3 saved files via FTP. Follow the FTP upload video in the Getting Started section of the class website for instructions on how to get a FTP client, and how to log in and access our class site. Navigate to your folder and choose the 3 files for upload. Once you see that all 3 project files are in your firstname lastname folder, you are done. FROM NOW ON You will follow the instructions on step 9 for every project, after the project is completed. You will always want to upload your finished project files to your folder on the class website. Don t forget! If your project is on your local hard drive, I cannot access it, I can only grade what is on the class website. FOR FULL POINTS MAKE SURE TO Upload all 3 images; resize, resample, and compression to your folder through the FTP client.