Assignment 2 ‐ Image Manipulation (Individual Project)

"For this assignment, every student has to prepare six digital images with different image manipulation techniques using graphic manipulation sofware, which is Adobe Photoshop. This assignment needs to be uploaded in your learning porfolio, which is your blog. A copy of the files in .psd format needs to be submitted also to the instructor using a CD‐ROM. The original images also has to be display side‐by‐side with the manipulated images. Explain also the image manipulation techniques that have been used to manipulate every image."

Image manipulation 1

To....

Image manipulation 2

To...

Image manipulation 3

to....

Image manipulation 4

Image manipulation 5

to...

Image manipulation 6

To...

Here's the scenario - a print shop/graphics designer/magazine asks a client for a photo at 300 dpi. They wish to print it out 7" x 5". The client already has a beautiful digital photo with pixel dimension of 2048 x 1536. The client notices that the photo editing software is showing that the photo is set to 72 dpi. So, following orders, the client types in 300 to reset the dpi to 300. In doing so the image is resampled and is enlarged over 4 times to pixel dimensions of 8533 x 6400. The client sends this enlarged 300 dpi photo. The print shop/graphics designer/magazine rejects it (too grainy, too colour blotched). The client is crushed.

The sad thing is that the client already had the perfect photo (2048 x 1536 @ 72 dpi) which would have been beautifully printed at 7" x 5" ( at 292.6 PPI). The print shop / graphics designer /magazine didn't know what they really wanted. - READ WHAT PRINT SHOP REALLY WANT and the client didn't know how to change the DPI without resizing the image to give the print shop what they mistakenly think they need - READ HOW TO CHANGE THE DPI..

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Peoples are always confused when deal with photo’s pixels, DPI and actual size. These are actually 3 properties/parameters that go into determining the resolution of a graphic.

Pixels: The exact number of 'dots' both horizontally and vertically that make up the file. This is the actual resolution of the file or the actual image size. The actual pixel is finite in a bitmapped file.

DPI (Dots per inch): The number of 'dots' or pixels per each inch of a printed or scanned document.

Actual size: The actual size is the physical size of a printed image or a scanned item.

These three properties have direct effect on one another. With any 2 of the properties you will get the third. Their relationship is stated in below formula:

Actual size = Pixels/DPI

If you look at the Image Size Menu in Photoshop you can see a little easier how these relate.

We can find out the size of our printing from above formula if needed. For example, if you have a 100x100 pixel image that is being printed at 100 DPI, the image would then be 1 inch by 1 inch when printed. If you have a 300x300 pixel image being printed at 100 DPI, the image would then be 3 inches by 3 inches when printed. If you had an image that was 300x300 pixels being printed at 300 DPI, it would print at 1 inch by 1 inch.

Many people think DPI is all that matters. They couldn't be more wrong! A person creating graphics for print often says "I need it at 300 DPI." That really doesn't tell us much. At least 2 properties that we mentioned above, i.e. DPI and Pixels, DPI and Size, or Pixels and Size have to be specified in order to output an image as required. For example, if I am scanning something that is 2" x 2" and I scan at 300 DPI, I will get an image that is 600 x 600 pixels. If my original was 8" x 10", I will get a result of 2400 x 3000 pixels. So if the person asking for 300 DPI also added that this image (when printed) will be 2" by 2", then we can do the math! We know that they want a final resolution of 600 x 600 pixels! We can do the math when we scan based on the size of the original.

As described in Case Study 3, the print shop/graphic designer/magazine ask a client for a photo at 300 dpi which they will use to print it out at 7” x 5”. So, they are actually asking for a photo which is in 2100 x 1500 pixels resolution. The client already has a good photo which is 2048 x 1536 pixels that able to fit the requirement with physical image size at 6.8 x 5.1 inches in 300 DPI.

2048 pixels / 300 dpi = 6.8 inches

1536 pixels / 300 dpi = 5.1 inches

The mistake happened when the requirement is not explain clearly to the client or due to the lack of understanding on dpi.

As we know, digital camera is the most common device that we use to create digital image. The resolutions of cameras are ranged from 10M to 21M in current market. A 10M camera can create a digital image in resolution 3872 x 2592 pixels whereas a 21M camera can create a digital image in resolution 5634 x 3753 pixels. Since the quality of a photo is mainly defined by the pixels, the DPI setting of a camera is actually meaningless. However, most of the cameras are set to 72 dpi since that is the original "screen resolution" of computer monitors. So, the digital photo of the client shall be created with a 3M camera since the image is 2048 x 1536 pixels @72 dpi. In order to fulfill the requirement of 300 dpi, the client chooses to resample the photo by changing DPI of photo directly from 72 to 300 with his photo editing software. However, with this resample, the pixel of the photo was enlarged by 4 times which we see a resolution of 8533 x 6400 now.

Most of the digital photos don't take well to this amount of enlargement without special techniques. So, grainy and color blotched was observed by the print shop and the photo is rejected.

What should the client do now? As we understand from above analysis, the resolution of existing photo is able to fit the requirement. He can just send the original photo to the print shop/graphic designer/magazine. Else, he can edit the photo with his photo editing software without resample after he change the DPI to 300 dpi.

Adobe Photoshop Method

Load your image into Adobe Photoshop (or Photoshop Elements).
Select the "Image > Image Size" menu option (may be "Image > Resize > Image Size" in Photoshop Elements).
In the image size dialog window, deselect the "Resample Image" checkbox (make sure there is no checkmark in that box).
In the "Resolution" box type in 300 (or whatever DPI you want)
Click the "OK" button
Your image DPI has now been set to whatever you want (leaving the pixel dimensions of the image unchanged).
Save this photo.