John, this is for you,

I modified your 16k Europa texture to approximate the colors rendered in the recent release (found here, for example). I stitched it all together, recolored etc in Photoshop, made a normalmap with the NVIDIA plugin, and retiled both. It is rendered in Celestia with some specularity. Just by eyeball, not bad...





If anybody wants to try and make it better, my parameters might be of use:

Coloring:
Color balance Highlights: -40 -5 +38
Color balance Midtones: -10 -5 +5
Color balance Shadows: +42 -10 +5
Layer duplicated with Soft Light blending on top, for enhancement of midtones.

NormalMap: From the original, desaturate, invert, NVIDIA plugin height 6, Surface filter radius 2 threshold 10.

Specularity:
SpecularTexture "europa-specular.*" # mask out the lines
SpecularPower 70.0 # from 0.00 to 100.00
SpecularColor [0.095 0.1 0.15] # RGB from 0.0 to 1.0

_________________
Guillermo Abramson
Bariloche, Argentina

i saw the nasa release and the post on UMSF
http://www.unmannedspaceflight.com/inde ... 300&st=140
and "Bjorn Jonsson's"
post 143
http://www.unmannedspaceflight.com/inde ... t&p=215903

i do think i do need to update it
BUT
a full map will look a but different than that one image
in the
http://www.jpl.nasa.gov/news/news.php?feature=4386
image

you can notice that it is "blueing" the closer one gets to the terminator , the light reflecting off the ice at a LOW angle has different properties than at a high angle
( ICE i like ROCK and regolith better even 67p-CG is basically BLACK )

but over all my ice dose need to be a bit more blue and the "dark" lines do need to be a bit more red

_________________
"I don't pitch Linux to my friends, I let Microsoft do that for me."
Using OpenSUSE Leap 15 & CentOS 7.6

Guillermo , very nice texture. Is this available for download/use yet?

Frank

Hey, Frank. I haven't uploaded neither Europa nor all the newest Saturnian moons that I have prepared. I will, eventually. I will let you know, I may prepare everything during the week end, given that I finished teaching the central forces problem in my course of classical mechanics today, and next week it will be my colleague who will start with small oscillations. Yay! I will have more time.

G

_________________
Guillermo Abramson
Bariloche, Argentina

Looking very good, Guillermo!

Fridger

_________________

Frank and everybody: I have packaged and uploaded Europa with new colors. It's a 16K virtual texture and normal map. Find it as always at:

http://fisica.cab.cnea.gov.ar/estadistica/abramson/celestia/

Saturn moons will follow (the 2010 textures are there, but there are newer maps now). Enjoy!

Guillermo

_________________
Guillermo Abramson
Bariloche, Argentina

Guillermo,

how did you settle on your final colors for Europa?

I am usually quite happy using the auto-coloration module in GIMP, together with
a natural color reference image.

Colors->Map->Sample Colorize

First of all, select the grayscale image to be auto-colored in the "Destination" slot (top left) and the RGB - colored reference image in 'Sample' (top right). Don't forget enabling RGB in the grayscale image!

Typically, the grayscale rectangular Europa map would reside in "Destination" and e.g. a Natural Color, global photo of Europa in "Sample".

Furthermore enable "Original intensity" and "Use subcolors". The other options may remain default. Start by clicking "Get Sample Colors". Finally hit "Apply" and examine the result...

Fridger

_________________

I tried the "match color" in Photoshop and didn't like the result this time. So I separated the smooth ice (white blue) from the lines and spots (reds) and manually tweaked the color balance to match the photo.

By the way, the .ssc I uploaded has a SpecularPower of 70, wich is too large. Change it to 1-5 to get something even more similar to the photograph. I will change the ssc in the uploaded file tonight.

G

_________________
Guillermo Abramson
Bariloche, Argentina

you might also want to state that these are dds images , on the download page .Not everyone can use them .

_________________
"I don't pitch Linux to my friends, I let Microsoft do that for me."
Using OpenSUSE Leap 15 & CentOS 7.6

As usual, your work is great. Thanks for the addon.

Frank