2008.09.07 23:18 "[Tiff] SAMPLEFORMAT_IEEEFP", by acanicio

2008.09.10 00:06 "Re: [Tiff] SAMPLEFORMAT_IEEEFP", by Chris Cox

They don't have to be between zero and one - but that is the default viewing range.

There are adjustments to change the value ranges, and a viewing exposure slider to change the viewing exposure.

I mean use the adjustment named Exposure in Photoshop to scale the data. If that works, then you can scale it when doing your conversion.

Chris

On 9/9/08 12:02 AM, "acanicio" <acanicio@astrosnap.com> wrote:

Dear Bruce and Chris,

Thank you!

I didn't know that floating point values had to be between 0 and 1!!

When converting to float, I kept the original range, i.e. 0..255 when coming from 8 bits, 0..65535 when coming from 16 bits, and 0..4294967295.

What do you mean by "Use the exposure adjustment "? Is there some specific tag for this or is it the same thing as scaling down?. I see tag TIFFTAG_REFERENCEBLACKWHITE in the specifications. Is that it?

I'll try as you say, thank you very much to both of you.

Use the exposure adjustment and scale the values down.

Most of the time, you should scale your white point to something near 1.0 to ensure visibility.

On 9/7/08 4:18 PM, "acanicio" <acanicio@astrosnap.com> wrote:

But I have no luck with floating point values. I use SAMPLEFORMAT_IEEEFP sample format along with 32 bits per sample.

All the pixel values are issued from an 8 bit/sample image, with no conversion or multiplication applied to them.

When I open the file with some well known image editor, the image is completely saturated, all white with values 32767...

Where should I look?