Search found 1559 matches

by jsachs
February 20th, 2011, 5:11 pm
Forum: Picture Window Support
Topic: Picture Window Pro 5.0.1.10 Posted
Replies: 5
Views: 1851

Re: Picture Window Pro 5.0.1.10 Posted

To count colors per channel, you can simply extract one or more of the channels and then count the colors in the extracted 16-bit B&W image. This is very different from counting the colors in a 48-bit color image however.
by jsachs
February 18th, 2011, 5:43 pm
Forum: Picture Window Support
Topic: Bit Depth of Raw Converter
Replies: 22
Views: 6140

Re: Bit Depth of Raw Converter

This is not a good test since the gamma curve that must be applied to the linear raw data is very steep near 0 (black), so large steps are to be expected. A better test might be a blue sky or a white wall exposed so that it does not max out any of the channels but where the variations should be very...
by jsachs
February 17th, 2011, 7:52 am
Forum: Picture Window Support
Topic: Bit Depth of Raw Converter
Replies: 22
Views: 6140

Re: Bit Depth of Raw Converter

If you email me a small (roughly 400x400 pixel) section of a converted raw file saved as a 48-bit TIFF I can check it with Count Colors here.

jsachs@dl-c.com
by jsachs
February 16th, 2011, 11:36 am
Forum: Picture Window Support
Topic: Bit Depth of Raw Converter
Replies: 22
Views: 6140

Re: Bit Depth of Raw Converter

As I mentioned in an earlier post, in PWP conversion from 8-bit to 16-bit is not done by simply shifting the bits left and setting all the low order bits to zero. Conversion is done by rounding to the nearest 16-bit level using the formula: v16 = (65535*v8 + 127)/255. Regardless, there are only 256 ...
by jsachs
February 16th, 2011, 8:04 am
Forum: Picture Window Support
Topic: Bit Depth of Raw Converter
Replies: 22
Views: 6140

Re: Bit Depth of Raw Converter

If all the values were in the upper 8 bits this does not mean that there would be no brightness levels below 50%, just that there are gaps between each brightness level. Using the readout tool however is a great way to see what is in the low order bits.
by jsachs
February 15th, 2011, 12:17 pm
Forum: Picture Window Support
Topic: Count Colors not working at 16/48bit ?
Replies: 2
Views: 846

Re: Count Colors not working at 16/48bit ?

You're right - I believe we will be reinstating this command (with a warning that it can take a very long time and use a lot of memory for large images) in the next maintenance release.
by jsachs
February 14th, 2011, 10:19 pm
Forum: Picture Window Support
Topic: Bit Depth of Raw Converter
Replies: 22
Views: 6140

Re: Bit Depth of Raw Converter

I'm not sure the method you are using to check the low order bits is reliable. You might try extracting one of the RGB channels from the image and then using the Window/Count Colors command. If it shows more than 256 colors then there is more than 8 bits of information in the channel.
by jsachs
February 12th, 2011, 8:29 am
Forum: Picture Window Support
Topic: Mixed text - italic and not italic
Replies: 2
Views: 939

Re: Mixed text - italic and not italic

Import the images into Microsoft Word?
by jsachs
February 6th, 2011, 7:36 am
Forum: Picture Window Support
Topic: Compositing 48 with 24 bit
Replies: 3
Views: 1192

Re: Compositing 48 with 24 bit

Not quite - conversion to the closest value is done by table lookup where v16 = (65535*(v8+127))/255 - conversion the other way is done by: v8 = (255*v16 + 32767)/65535.
by jsachs
February 5th, 2011, 8:00 pm
Forum: Picture Window Support
Topic: Compositing 48 with 24 bit
Replies: 3
Views: 1192

Re: Compositing 48 with 24 bit

When compositing 24-bit and 48-bit images, the result is always a 48-bit image, regardless of which is the base and which is the overlay image. The 24-bit image is automatically converted to 48-bit before compositing.