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Thread: HT and CT

  1. #1
    muyisoldier
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    Question HT and CT

    What is the difference between HT and CT for a printer color management in EFI program ? Which is better?

  2. #2
    Donor Apa_Cska is on a distinguished road
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    Quote Originally Posted by muyisoldier View Post
    What is the difference between HT and CT for a printer color management in EFI program ? Which is better?
    The HT is the old methode, everything is controlled by EFI driver.
    CT is a new solution, when some standard paper are optimized by the printer manufacturer in the firmware of the printer. So you dont need to limit the inks or linearize, 'cause it is wired in the printer (to this standard media), so you can drive the 6-7...-11 ink printer as a simple cmyk device. (Usually it's faster, and means higher gamut also. Unfortunately older inkjets lacks of it.)

    Ap

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  4. #3
    muyisoldier
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    Quote Originally Posted by Apa_Cska View Post
    The HT is the old methode, everything is controlled by EFI driver.
    CT is a new solution, when some standard paper are optimized by the printer manufacturer in the firmware of the printer. So you dont need to limit the inks or linearize, 'cause it is wired in the printer (to this standard media), so you can drive the 6-7...-11 ink printer as a simple cmyk device. (Usually it's faster, and means higher gamut also. Unfortunately older inkjets lacks of it.)

    Ap
    Thank U~ , i see that.
    I thought CT is short for continuous tone and HT for halt tone

  5. #4
    Donor T. Schruda is on a distinguished road
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    CT means contone.

    as APA said, the printer recieves RGB data and splits it up to its colors (CMYK+whatever)

    HT.. the RIP sends the screening per ink channel of printer

  6. #5
    Junior Member Odystar is on a distinguished road
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    There are some advances in HT as well:
    - you have more controls while linearizing what is valuable for some nonstandart papers
    - you have a possibility to use all of the available resolutions for the printer: using simmetrical (1440x1440) resolutions may be critical on Epsons when you are using OneBit option

    Though, for CMYKOG printers I prefer CT because for HT you have to profile for 6CLR as well.

    Regards

  7. #6
    PRC Member lessbones is on a distinguished road
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    Quote Originally Posted by T. Schruda View Post
    CT means contone.

    as APA said, the printer recieves RGB data and splits it up to its colors (CMYK+whatever)

    HT.. the RIP sends the screening per ink channel of printer
    Its actually CMYK data that the printer is receiving with the CT driver, the printer is just splitting it into whatever other inks you may have on the side (light black, light cyan, etc) although Schruda I seem to remember you saying your printer has RGB inks also? Maybe its somewhere in that CMYK-CMYKRGB translation that you're losing black density...

  8. #7
    Donor T. Schruda is on a distinguished road
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    well.. it depens of course where you use the CT driver and how.

    if you dont use a RIP than the printer will always use the CT driver.

    and there you can usually ONLY send RGB data that the CT driver will then split to what ever.. CMYK or ClmMYKlKllKRGB.. in my case.

    if you use a RIP than you can send CMYK data to the printer.. and the CT driver will split it like lessbones sess.. if you use the RGB function of EFI f.e. then you can send RGB data again.

    if you have a PS version printer then you can also send CMYK data to the printer that will be split up by the CT driver

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  10. #8
    Junior Member rhguru is on a distinguished road
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    CT is a good and fast solution for most proofing cases.
    But when you need better control of light ink implementation or when you're playing with dot proofs I would suggest to use HT, then it gives more detailed dots than when goes with CT.

  11. #9
    Junior Member yazh is on a distinguished road
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    CT means efi will use cmyk driver from manufacturer(cmyk) while HT mode using cmyk&multichannel driver from efi(CMYKOGcmkk)

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