Image subsamples

Applies to: Version 4

The Timestone Administrator allows the user to define sets of subsampled image previews that will be created upon importing images into the Version 4 applications. The user can then select a set when starting a new job and then switch to the desired image preview size at any stage while working with the job. Image subsamples are stored in the auxiliary files (see Auxiliary files)

Why use subsamples?

In Version 3 and earlier the default preview size for images is 512K. This is adequete for general image editing but many situations may present where the user may wish to use bigger or smaller sizes. For example when working with the Chroma Key module it is advisable to use a bigger preview size to achieve better results. Similarly when using the 'printing with thumbnails' option a larger size may be required.

To achieve the desired preview size in Version 3 the user is required to change the size in File>Properties then refresh all the images. With Version 4 different sizes can be predefined as a subsample set in Timestone Administrator. The user can then select the desired image preview size at any stage without the need to refresh all the images. Furhermore Version 4 allows for a different subsample set to be used for group images in NeoGroup and GroupBuilder where image preview quality needs to be greater than that for portrait images.

Defining a subsample set

To define a set of subsamples launch the Timestone Administrator and select the Subsamples object. A 'default' set at 512K is already present at a subsample size of 512K. Extra sizes can be added to this set or alternatively a new set can be created at the desired subsample size.

Figure 1: Adding subsamples.A 2048K subsample has been added to the default set.

Using subsample sets

If more than one subsample set is defined the user may select which set to use when starting a new job. At any subsequent stage a different set can be selected with the File>Properties window.

Figure 2: Selecting a subsample set. A new job is being started with the "Big Previews" subsample set.

Changing the preview size

Once a subsample set has been selected it is possible to change the previews to any of the sizes defined for that set via the File>image previews ... window. It is not necessary to refresh the images once the new preview size has been selected.

Figure 3: Changing the preview size.Image previews can be changed to any size defined for a given set.

Using the MySQL thumbnail

As noted in the article, Auxiliary files), the MySQL database only stores a tiny (approximately 12K) thumbnail which is mainly used for the Timestone Software Internet Ordering System. All other image previews are stored in the job's auxiliary file.

The thumbnails, like the subsampled previews, are available to use at any time however they result in very "crunchy" images and so their use is limited. Switching to the thumbnails is very useful when exporting a job to tnj file since they will result in the smallest possible tnj job file size.

Avoiding long import times

Subsampled images are created when importing the images into a job. Each set and each size are resampled from the original images when they are imported and written to the auxiliary file. This process takes time. To avoid lengthy image import times it is recommended the user only define as many subsamples as required.

End of article