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Saving OpenEXR Files 623
S avi ng OpenEX R Files
Render Scene dialog > Common panel > Common
Parameters rollout > Render Output group > Click Files.
> E nter file name and set type to OpenEXR Image File >
Click Save. > OpenEXR Configuration dialog
RenderedFrameWindow>ClickSaveBitmap.>Enterfile
name and set type to OpenEXR Image File > Click Save. >
OpenEXR Configuration dialog
Use the OpenEXR C onfiguration dialog dialog to
set output p arameters for OpenEXR fi les. You can
specify the format for saving the RGBA data as
well as w hich of the four standard channels should
be saved. An option is available to use RealPixel
unclamped color information for Render Output
saving. Also available are color transforms to be
applied, file compression type, and additional
attributes.
Inter face
Co mpression Type—Lets you choose the method
of fi le compression. The OpenEXR API
provides for three general typ es of lossless
compression, including two different methods of
Zip compression. For most images without a lot of
grain, the two Z ip compression methods seem to
work best, whi le the PIZ compression algorithm
is better suited to grainy images. The following
options are available:
•
None—Disables all compression.
•
RunLengthEncoding(RLE)—Abasicform
of compression comparable to that used by
standard Targa files.
•
Zip (per scanline)—Zip-style compression
applied to individual scanlines.
•
Zip (16 s canli ne block s)—Zip-sty le compression
applied to blocks of 16 scanlines at time.
Thistendstobethemosteffectivestyleof
compression to use with rendered images that
do not have film grain applied.
•
PI Z ( wavel et compression )—Uses a combined
wavelet/Huffman compression. This form of
compression is b est for g r ainy images.
Standard Channels group
The standard channels in an image are: red, g reen,
blue, and a lpha (transparency). This group lets
you choose the gener a l type of OpenEX R file to
save,aswellaswhichofthefourchannelstosave
w ith the file. The most widely supported format
is Half Float - 64 bpp format. This stores each
channel of the image in a separate slice in the file
using half-type 16-bit floating-point data. The
OpenEX R distribution has features that allow easy
implementation of reading and writing this type of
file, and it is considered a standard OpenEXR file.
Forma t—Choose one of the following from the
drop-down list:
•
Integer - 3 2 bpp—This non-standard OpenEXR
format contains only a single 32–bit integer
channel. It uses a packedIntRGBA image type
in order to support old-style bit depths, such as
32–bit Targa fi les. Only this plug-in can read
this format.
•
Half Floa t - 64 bpp—This 16-bit-per-channel
“half-float” format is standard OpenEX R. Any
software that supports OpenEXR can use t his
format.
•
Float - 12 8 bpp—The 32-bit-per-channel
“full-float” format is encoded using st andard
OpenEXR channel tags. Most OpenEXR
implementations will have no problems reading
this format.