# Licensing and prices for print media

Media on this site is either published under Creative Commons Attribution-Share Alike 4.0 license (CC-BY-SA 4.0) or under Creative Commons Attribution-Noncommercial-Share Alike 4.0 license (CC-BY-NC-SA 4.0). This allows to use it freely in many cases, especially non-commercial ones.

For most print media, there exist fixed price schemes which are described below.

For other licensing options, or if it is unclear whether media can be used freely, please contact me via email. Address can be found in imprint section.

## Prices for magazines

The prices roughly reflect the quality (SNR is approximately proportional the the square root of the amount of photons captured) and the effort. The prices help to finance my projects -- at least a small fraction of their costs.

Price P for magazines is calculated by the formula

P = max{1 EUR, √ T · A  · I} · C

where

T
is the total exposure time of all data used for the (single or multiple) variant(s) you want to publish. That means, if an image is available in two variants which only differ in the color order, you can use one or both variants for the same price.
A
is the area factor for mosaic images if not the full image is published. That means, if the field of view (FOV) of the image is larger than the FOV of the camera, that factor A is area of the published FOV divided by the area of the total FOV, where at least the FOV of the camera has to be purchased. E.g. the area factor A is 0.25 if 25% of a 3×3 mosaic is published. For non-mosaic images (FOV of camera larger or equal than FOV of image), or if the full image is published, area factor is always 1.
I
is the instrument factor which depends on optics and camera:
C
is the number of paid copies (printed or eMedia) divided by 1000
If the product  T · A  · I is less than 1 EUR, the price is calculated by P = 1 EUR · C. That minimum is also applied if total exposure time is not specified.

### Example

If you want to publish that crop of Barnards Loop from the wide-field view on Orion, you have to pay for 28% (area factor A, because the crop only covers 28% of the area of the full view) of the H-alpha data (currently 7.5d) and continuum data (currently 4.3d). Instrument factor I is 6 EUR/d0.5. That results in  T · A  · I =  (7.5d+4.3d) · 0.28  · 6 EUR/d0.5 = 10.5 EUR. That is above the minimum of 1 EUR, i.e. you have to pay 10.5 EUR per 1000 copies and you also can publish the RGB variant and the H-alpha image at no additional costs (because they base on the data you already paid for).

## Prices for calendars, posters, ...

Price P for this kind of media media depends on the selling price:

P = 0.2 · n · s · r

where

n
is the number of sold copies
s
is average selling price per copy
r
is appearance ratio. For example, if the image appears during 30 days in a year calendar that factor is r=30/365. For posters that ratio is 1.

## Purchase, technical support

For purchases and technical support, please use the email address stated below. Because images in this site are optimized for monitors, there are some recommendation for conversion to print media:
• A tonal curve correction is recommended. For this purpose 16 bit images can be delivered.
• For wide-field / high resolution images: Do not use a higher resolution than necessary. For down scaling by factor n, use a n×n median filter and than downsample by factor n (that also can be done for you on request). The reason is, if you try to depict all faint stars the background looks gray an noisy. With average filtering it looks gray but less noisy. For this reason a median filter should be used.

On the other hand, dark nebula can be better visualized if star-rich regions (not covered by the dark nebula) look gray (and more or less noisy).

• Pictures here are usually false color images. When converting them to other color models, it is not necessary to try to preserve any colors. Instead of this it is recommended to translate the colors such that the used color space is as large as possible. If more than 3 printing colors are used it is even possible to compose the images from more than 3 colors (on request).