Best way to apply vibrant colors to Full Color Sandstone

Discussion in 'Design and Modeling' started by BrettWoodard, Jul 23, 2014.

  1. BrettWoodard
    BrettWoodard New Member
    I have been printing some models in Full Color Sandstone (FCS) and have a couple of questions about the best file format to export the models. I am from a computer aided design background, currently working with ViaCad9 and have no experience with UV color maps. To apply color, I have been setting the color of individual parts that make up the model and exporting using VRML2 (.WRL) format. Similar to the Radioactive Barrel posted below.

    RadioactiveBarrellVerySmall.jpg

    Assuming that I am not interested in more complex coloring (like gradients), are there any advantages to importing the model into other programs and creating UV color maps?

    Sometimes, I feel like the colors I print do not always seem as vibrant as some of the colors done by other modelers on Shapeways and I was wondering if it was related to not using color maps.

    I am willing to learn UV mapping, just not sure if it is a good idea for simple color schemes of parts. Appreciate any thoughts or suggestions.

    -Brett
     

    Attached Files:

  2. mkroeker
    mkroeker Well-Known Member
    UV maps as such will not automatically make your colors more vibrant, all they do is provide a (relatively) easy means to add gradients and surface details that do not have to match the underlying mesh. So for your barrels, it could be that you are simply using a wrong shade of yellow. The zcorp printer does not reproduce all colors equally well - there are a few test palettes in the shops to check this and make it easier to find nice looking RGB values. If on the other hand you wanted to make a very rusty version of your barrel, uv mapping would be the only way to paint the spots on, unless you made your mesh extremely detailed just to have vertices in the right place that you could assign the colors to.
     
  3. BrettWoodard
    BrettWoodard New Member
    mkroeker,

    Thank you for the reply. I hadn't thought about the printer not being able to print all colors equally well. I will have to search out some of the test palettes you mentioned in some of the shops.

    I was reading the tutorial at the link below and it said the ZCorp printer Shapeways has uses a CMYK color scheme. Do modelers find their colors come out better in FCS if they generate UV maps or VRML files using CMYK color scheme since this will match how the printer determines colors?

    https://www.shapeways.com/tutorials/designing-for-better-col ors-in-full-color-sandstone

    -Brett
     
  4. mkroeker
    mkroeker Well-Known Member
    That question is a bit academic as VRML supports RGB colorspace only (as do the supported texture file formats as far as I know).
    On the topic of palette samples , stannum has a nice one here that is accompanied by an image of the colormap on the model page so you can pick color values from it directly. Another set by kaetemi is here. he suggests scanning the actual print to create your own colormap file from it. (Somehow stannum's approach seems more logical to me - to choose a visually adequate result from the printed palette and then look up the input color required to achieve it).
    Also note the thread linked from the end of that tutorial you mentioned - varnishing the print can improve the colors (probably because it makes the surface smoother,i.e. less prone to light scattering - I was recently surprised to learn that the raw fcs print barely shows colors before the superglue coating is applied)
     
  5. BrettWoodard
    BrettWoodard New Member
    After doing a little research of my own, I understand what you mean by academic since Shapeways only supports VRML2 and 3 texture formats. The VRML2 file format appears to only support RBG ( http://www.graphics.stanford.edu/courses/cs248-98-fall/Assig nments/Assignment3/VRML2_Specification/spec/part1/glossary.h tml). PNG and GIF only support RGB. Depending on what source I read, JPG either only supports RGB or can support CMYK as well. Though it seems the support for JPG CMYK is not robust.

    Thank you for the information. I'm gathering the answer is two pronged.
    1. Make sure I consider that colors will have to be transferred from RGB to CMYK for printing.
    2. consider finishing the FCS parts if I really want the colors to stand out.


    Other file formats.
    PNG - RGB
    GIF - RBG
    TGA - RGB
    JPG - RGB/CMYK?
    TIFF - RGB/CMYK
    PSD - RGB/CMYK

     
  6. mkroeker
    mkroeker Well-Known Member
    Also bear in mind that this is a "simple office inkjet" (three colors plus black) printhead while current photo printers have at least six colors to mix from, and printing on coarse off-white gypsum instead of coated titanium white paper is not going to help color fidelity either.
     
  7. AmLachDesigns
    AmLachDesigns Well-Known Member
    @BrettWoodward - the only file formats for UV Texture upload are: GIF, JPG, PNG

    @mkroeker - are the printers not cmyk and therein lies some of the problems?
     
  8. mkroeker
    mkroeker Well-Known Member
    That's what he wrote.

    That's what I meant - though please ignore my roundabout rambling, boil a frog contest currently on in this flat top office building with no aircon. The photo printers either combine one set of cmyk and rgb each, or cmyk with lighter tones of cyan and magenta to achieve a bigger color range.
     
  9. AmLachDesigns
    AmLachDesigns Well-Known Member
    Re: the file formats - you are right (both of you), my apologies. I guess I was confused by the list of files at the end of the post, some of which are not relevant to SW. Plus I too am suffering from the temperature and humidity...