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#11
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Why a Rasterizer ?
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#12
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Why a Rasterizer ?
"Talal Itani" wrote:
Inkjet printers, like the Canon I have, have a resolution of 4800 x 2400 dpi. When I use a loupe, I can see the very very tiny dots. The dots are tiny when the colors are light. When the colors are dark, the high-resolution is not maintained. I wonder if you are seeing halftone dots. Some inkjets will use halftones, others dithering. Where halftones are used you will see dots that grow from very small to large and eventually join. The separation of these dots is the "lpi" value, and probably something like 150-200. This is the effective resolution of color detail. The finest colour detail, in highest quality professional printing, is probably around 300 lpi (wild guess). However, it's worth noting that, unlike many lasers and imagesetters, the high resolutions quoted for inkjets are nominal; 2400 dpi does not imply a smallest possible dot of 1/2400 inch. ---------------------------------------- Aandi Inston Please support usenet! Post replies and follow-ups, don't e-mail them. |
#13
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Why a Rasterizer ?
It depends how small the text, the kind of material on which it is printed, and the font used. As an experiment ! printed a range of sizes from 1 point to 2 points on a Xerox 2025 at 1200 x 1200 genuine set at 120 lpi. On uncoated papeer 1 point is illegible and 1.5 is readable under the loupe. On coated paper 1 point is readable under the loupe using a bold font. Xerox has produced a MicroText system to 'print' at 1/100 of an inch for security douments so I assume 0.75 point is the size to emulate. Would microfilm techniques be another method? I tried microfilm, yet since microfilm is gray-scale, things did not look nice and sharp. The output looks very good on a black/white film imagesetter, also good on coated imagesetter paper. I did read about the MicroText from Xerox. This is a font. I assume the Xerox MicroText font can be used on some of their printers. There is also the option of a digital printing press, which I have not tried. Surely I will not buy one, but I will try a service. |
#14
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Why a Rasterizer ?
"Aandi Inston" wrote in message ... "Talal Itani" wrote: Inkjet printers, like the Canon I have, have a resolution of 4800 x 2400 dpi. When I use a loupe, I can see the very very tiny dots. The dots are tiny when the colors are light. When the colors are dark, the high-resolution is not maintained. I wonder if you are seeing halftone dots. Some inkjets will use halftones, others dithering. Where halftones are used you will see dots that grow from very small to large and eventually join. The separation of these dots is the "lpi" value, and probably something like 150-200. This is the effective resolution of color detail. The finest colour detail, in highest quality professional printing, is probably around 300 lpi (wild guess). However, it's worth noting that, unlike many lasers and imagesetters, the high resolutions quoted for inkjets are nominal; 2400 dpi does not imply a smallest possible dot of 1/2400 inch. ---------------------------------------- What about digital printing presses that are advertised as 2400 x 2400 dpi? These are the big machines, made by Xerox, Oce, Indigo, and a few others. |
#15
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Why a Rasterizer ?
"Talal Itani" wrote:
However, it's worth noting that, unlike many lasers and imagesetters, the high resolutions quoted for inkjets are nominal; 2400 dpi does not imply a smallest possible dot of 1/2400 inch. What about digital printing presses that are advertised as 2400 x 2400 dpi? These are the big machines, made by Xerox, Oce, Indigo, and a few others. These million dollar machines should be true to their quoted resolution. They aren't inkjet. But they can be expected to use halftones. One key reason for this is that many paper/ink conbinations have a minimum effective dot size. They may not be suitable for your highly specialised application. Indeed, it's hard to imagine that ordinary paper can deliver at all. Printing on photographic paper with an imagesetter may deliver what you need. ---------------------------------------- Aandi Inston Please support usenet! Post replies and follow-ups, don't e-mail them. |
#16
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Why a Rasterizer ?
However, it's worth noting that, unlike many lasers and imagesetters,
the high resolutions quoted for inkjets are nominal; 2400 dpi does not imply a smallest possible dot of 1/2400 inch. What about digital printing presses that are advertised as 2400 x 2400 dpi? These are the big machines, made by Xerox, Oce, Indigo, and a few others. These million dollar machines should be true to their quoted resolution. They aren't inkjet. But they can be expected to use halftones. One key reason for this is that many paper/ink conbinations have a minimum effective dot size. They may not be suitable for your highly specialised application. Indeed, it's hard to imagine that ordinary paper can deliver at all. Printing on photographic paper with an imagesetter may deliver what you need. Thanks. This is very true. I am giving up on printers. You are right, imagesetters are expensive, and they are hard to own. When I use an imagesetter service, the cost per sheet is high, and there is the hustle of sending files and receiving the output, and the cost of mailing. Maybe I can find a 'small' 'easy to own' 'inexpensive' imagesetter, yet maybe that is impossible. I always outputted to film. I wonder if I can output on white paper. |
#17
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Why a Rasterizer ?
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#18
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Why a Rasterizer ?
I'm not sure you are understanding the printing process for inkjet printers fully. There are several differing inkjet printing technologies used. For instance, Canon and Eposn do not use the same methodologies/ The Canon printer uses a thermal head which literally heats the ink at the very tip of the head and when it boils that change of state causes the gaseous state to provide pressure to expel a droplet of ink to the paper. This method doesn't allow for much variation in dot size. As a result, Canon heads (depending upon the model) have three sets of nozzles. The very small dots you speak of are not produced by the same ink nozzle as the larger ones are. A larger dot is used to create larger denser areas of color. The Epson head, as one example, is called a piezo mechanism. Unlike the Canon, it is a cool (as in temperature) method that involves the piezo actuator vibrating and that frequency causes the fractionation of the liquid ink which is then expelled through the nozzle in the head. In the case of Epson printers each nozzle is used for between 3 and 7 drop sizes, depending upon the model specs. The nozzle is large enough to allow even the largest dot size to get through as well as much smaller ones. Art If you are interested in issues surrounding e-waste, I invite you to enter the discussion at my blog: http://e-trashtalk.spaces.live.com/ Talal Itani wrote: Your explanation brings another question: 'why do some printers require a dedicated RIP box?' Well, understand that the "rasterizer" is always a separate computer dedicated to the task of rasterizing. Some printers depend on your host Windows/Macintosh computer to do the raster processing, others install the RIP computer inside the same case with the laser engine, and others place the RIP computer outside in its own case. But in every case, there's a separate RIP. In two of the three cases above, it's a dedicated RIP. In high end situations, you want to separate the RIP from the engine. In all cases the output of the RIP is a raster pattern that the engine can use, but inside the RIP can have many different features. To facilitate giving the customer what he wants, it's far easier to let him pick and choose the RIP features separate from the engine features. ok. That made sense to me. Inkjet printers, like the Canon I have, have a resolution of 4800 x 2400 dpi. When I use a loupe, I can see the very very tiny dots. The dots are tiny when the colors are light. When the colors are dark, the high-resolution is not maintained. This is because the rip of the printer is very powerful, and the rip cannot address every single dot individually. I have a project that requires high-resolution, and being able to address every single dot individually. I learned that a separate RIP can be purchased for this task. Do you know more about this? Thanks. |
#19
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Why a Rasterizer ?
OK, I stand corrected. I wasn't sure, which is why I prefaced my remark with 'AFAIK'. Thanks for the enlightenment.
-- Cheers, cmyk "Elmo P. Shagnasty" wrote in message ... In article , "cmyk" wrote: AFAIK, Laser printers, however, only quote the actual hardware resolution as they're unable to vary the amount of toner at a given location - it's an all-or-nothing affair. No, not at all. They can modulate the intensity of the laser at a certain dot, and many high end color lasers can do 600x600x8--that is, 600 dots per inch at 8 bits per spot, for 256 shades per spot. |
#20
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Why a Rasterizer ?
[A complimentary Cc of this posting was sent to
Talal Itani ], who wrote in article Bvwbk.794$al3.102@trnddc06: ok. That made sense to me. Inkjet printers, like the Canon I have, have a resolution of 4800 x 2400 dpi. When I use a loupe, I can see the very very tiny dots. The dots are tiny when the colors are light. When the colors are dark, the high-resolution is not maintained. This is because the rip of the printer is very powerful, and the rip cannot address every single dot individually. I have a project that requires high-resolution, and being able to address every single dot individually. I learned that a separate RIP can be purchased for this task. Do you know more about this? I can't give you the exact answer (and the answers you got here do at least look "very reasonable"), however, I want to point you to either some code which DOES work directly with "dots" (as opposed to "pixels") of a printer, or the people who wrote this point. Take a look at http://gutenprint.sourceforge.net/gu...ers-manual.pdf In particular look at the last clause of 6.1.8, (8): Applications with special requirements can now access the raw ink channels directly. This facility was used to create a mechanism to more accurately tune printer inks. Looking around this page (p.41), one can guess that this code may be accessing ink drops more or less individually. I would guess that using (some modification of) this code, one could position drops with the granularity restricted by hardware only. (Moreover, looking at the code, you might be able to find out what are EXACTLY the limitations of the hardware.) [Keep in mind that other answers in this thread discuss more or less limitations of HARDWARE + THE PRINT DRIVER. The code above may have fewer limitation.] [Disclaimer: I myself did not look at the code in question, only looked through the user docs. Better try to contact developers first...] Hope this helps, Ilya |
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