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Quicktip: Scanning 35mm film for Full HD TV output

January 29th, 2010 · No Comments · analogue photography, Digital Photography, HowTo

The previous three articles (I, II and III) should provide users with the necessary tools for managing resolution in SilverFast.

And the introductory article Scanning for TV explains some common issues to be taken into consideration.

Scanning pictures for a Full HD TV set is typical example of what you can do with the aid of the resolution panel.

Common Difficulties

-Aspect Ratio

The aspect ratio is the quantitative relation between the longest side (dimension) to the shortest side of a picture. It expresses the number of times one value contains the other, or how many times one value is contained by the other.

Every photographic film format has a different aspect ratio as well as different television sets.

The standard ratio for a Full HD tv set is 16:9 (or 1920 x 1080 pixels)

Full HD tv, aspect ratio 16:9

Full HD tv, aspect ratio 16:9

Different Film formats have different aspect ratios.

35 mm film have an aspect ratio of 3:4 (25mm x 35 mm).

35 mm film or slide. Aspect ratio 4:3 (35x24 mm)

35 mm film or slide. Aspect ratio 4:3 (35x24 mm)

Since these aspect ratios do not match, you will either have to crop the picture as to match the tv aspect ratio or to scan the picture and have two black bars on either side of the image when watching them on the tv (note how the tv has a larger side than the film in relation to their smaller side ).

– Storage and display options

If you want to have your pictures on DVDs, you gotta have in mind that DVD s is not a high definition format. DVD players were designed to work with the resolution of 720 dpi on its largest side. This resolution is nothing close to that of a Full HD tv., if you burn images which are bigger than DVD resolution, the player might have problems downscaling those images and might take a lot of time displaying every picture.

In such cases is better to scan the pictures to match the DVD resolution.

Game consoles like Xbox 360 or Playstation 3 are high definition devices designed to work with such imagery. These devices have powerful imaging processors capable of down or up scaling pictures. It should not be a problem to read DVD with high definition images with these devices.

Using hard disk drives to store pictures is a different option, which also present two possibilities. most Full HD tv sets have a USB 2.0 port and are capable of reading media directly from external devices (like hard disks, memory sticks, memory cards, etc.). The TV should not have a problem to read pictures with the same size, however reading bigger pictures can be problematic, here the downscaling can also take some time depending on the tv. If you connect a computer and read the pictures from there, the computer should not have problems with this.

The best thing should be to move within that range and avoid using larger resolutions, unless you plan to use the picture in a video, to zoom in and show details eventually moving within the picture, then you are going to need much more resolution but this should be imported into a video editing suite which at the end will create the correct output format.

These aspects should be considered before scanning your pictures to avoid having to repeat the scanning of the pictures.

If you are not too sure, or you want your pictures for different purposes then it is better to scan them at the highest optical resolution for archival and use those files as starting point.

Setting SilverFast for the job

Say we”ve decided to digitize the pictures to match the entire tv screen, then I will have to crop some details from the upper and lower sides of every slide.

First make a prescan and then set the scanning frame to the correct aspect ratio, that is the desired output aspect ratio. In this case Full HD tv, 16:9. The scanning frame should be of course within the area of the image.

The easiest way is to draw a frame that surrounds your entire slide.

Preview and scan frame

Preview and scan frame

In the resolution panel, change the unit to pixels and click on the field that presents the value for the largest side (horizontal) and enter the value of the tv screen’s largest side, in this case 1920 pixels.
Note how the vertical value automatically changes to 1270 pixels (or something similar).

Unit and horizontal value change

Unit and horizontal value change

Now re-size the scanning frame in the preview window by dragging the lower side upwards with your mouse. This has to be  done carefully, while checking at the same time the vertical output value until you reach the desired value of 1080 pixels.

Drag the lower side of the scanning frame to resize

Drag the lower side of the scanning frame to resize

Great! the desired scanning frame is ready, now it is just a matter of placing it in the right position.

To prevent any accidental change from happening you can close both locks at the left side of the horizontal and vertical output fields.

Close the locks

Close the locks

You can now move the scanning frame to the desired position of the image (cropping it either on the upper and lower ends)

Or you can even re-size it without changing its aspect ratio (to include the entire image plus two black bars at the left and right sides).

Resize and relocate to include the entire image (plus black bars to the right and left sides)

Resize and relocate to include the entire image (plus black bars to the right and left sides)

You can now press the scan button and save your image in the desired folder.

To prevent loosing the scanning frame, you can save it under the “general” tab and menu “Frame-set” option save and load it in the future.

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