All posts tagged RGB

Comparing RGB Stripe Text to PenTile RGBW Text

My post showing the comparison of fonts with RGB stripe to PenTile RGBW LCD and PenTile RGBG OLED still left a few people confused, so I am going to illustrate this one more way.  Previously, I compared the results for the same number of columns.  Since PenTile RGBW can represent the amount of information in one-third fewer columns my prior blog showed the PenTile RGBW with one-third more font information.

This time I am comparing the same amount of font information, where PenTile RGBW used one third fewer columns, but have stretched the columns horizontally to match the horizontal space of the RGB stripe, just as it is done in products today.  This allows the comparison of equivalent size single stroke Arial fonts between RGB stripe and PenTile RGBW.

RGB Stripe (Top) - PenTile RGBW (bottom) As Rendered (left) - Blurred to Simulate Viewing Distance (right)

 

Perhaps you may wonder why there are some color subpixels turned on in places such as the vertical stroke of the “D”.  The reason is that if viewed at the normal distance, and if these subpixels were turned off, such a rendering would cause a color error to the white that was adjacent to the black line.  Rendering this as has been done prevents such color error at the edge of this font.  And, yes the PenTile RGBW should look brighter than the RGB stripe since this is a representation of the relative light transmission of PenTile RGBW vs RGB Stripe

The only problem is that this magnification is not at all how the human vision system sees this.  At the viewing distance for which this is design, that which you see will be blurred to hide the subpixels.  Move away from your screen until the subpixels on the lft hand images  are not apparent and you will see this as finished product would appear.

Moving away from the display has also be emulated by taking the images on the left and blurring it in Photoshop HSL space to create the images on the right that more accurately represent how the vision system sees these font renderings.

Perhaps you may wonder why there are some color subpixels turned on in places such as the vertical stroke of the “D”.  The reason is that if viewed at the normal distance, and if these subpixels were turned off, such a rendering would cause a color error to the white that was adjacent to the black line.  Rendering this as has been done prevents such color error at the edge of this font.

The only problem is that this magnification is not at all how the human vision system sees this.  At the viewing distance for which this is design, that which you see will be blurred to hide the subpixels.  Move away from your screen until the subpixels are not apparent and you will see this as finished product would appear.

Moving away from the display has also be emulated by taking the image on the left and blurring it in Photoshop HSL space to create the images on the right that more accurately represent how the vision system sees these font renderings.

Fonts – comparing RGB Stripe to PenTile

As promised, this blog will illustrate small fonts compared between RGB stripe LCD, PenTile RGBW LCD and PenTile RGBG .

In the comment from Khalid H. he said that Arabic fonts cannot be read on his HTC phone equipped with PenTile, implying that PenTile cannot render Arabic fonts.  Unfortunately, Khalid did not mention what font size or style of Arabic font, and there are so many. I borrowed a clipped section of an Arabic font from Middle East International Services (http://www.dalilusa.com/arabic_course/text01.asp). I displayed these fonts on my PenTile RGBW LCD and tried to photograph these incredibly small fonts.  Even with the best lens on a Canon SLR, I went beyond the resolution limits of this lens to get a sufficient focus.  So instead, display simulator tools were used to render these characters in RGB stripe, PenTile RGBW and PenTile RGBG as is used for OLED.

I have to agree that I could not read these on PenTile, but then I also could not read these on RGB Stripe, since I do not read Arabic.  Just the same, I am posting the comparison between RGB Stripe, PenTile RGBW and PenTile RGBG .  I compared  these using an eye loop to the actual fonts displayed on our PenTile and RGB stripe screens and the rendering is matched exactly.  As you can see below, the comparison speaks for itself.  PenTile RGBW and PenTile RGBG can render these tiny single stroke fonts equivalently to RGB stripe.  Even the white dot in in the small square is rendered perfectly, or at least it seems that way to a non Arabic reader, but in any case it too compares well to RGB stripe.

The relative brightness is a true representation of how PenTile RGBW will appear on a screen at comparable power.  In each case there are 600 pixels of width, but with PenTile we eliminate one-third of the subpixels, so 600 pixels includes more information than for RGB stripe.

RGB Stripe LCD

PenTile RGBW LCD

PenTile RGBG OLED

For good measure, I did the same exercise with an Arial, English letter font.  Ariel was chosen because there were good options for small single stroke fonts.  I cannot see any problem with how this is being rendered in PenTile.  While some may say that fewer subpixels should lead to fuzzy fonts, it simply is not true.

RGB Stripe LCD

PenTile RGBW LCD

PenTile RGBG OLED

These fonts are zoomed in to a level that one should never look at fonts.  Both PenTile and RGB stripe are looking rather jaggy.  That is true for both RGB stripe and PenTile displays.  Of course, large fonts that are not single stroke, especially when displayed on larger diagonal displays can look better than these small fonts, except that they too will also look more jaggy at the edges.  PenTile is never recommended for low dpi, not because it renders incorrectly, but because the pattern will become visible at lower dpi.

Note that I did not try to test these on phones or with specific types of software, because I don’t have access to the wide variety of phones that some bloggers seem to have.  There are variations in SW and other factors unrelated to PenTile that can make these images look different than the rendering engine is capable of producing.

 

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Update in response to the comment from Khalid H. last weekend.  He suggested that such disconnected fonts were not as difficult and suggested that we look at Arabic Droid fonts which are more connected.  With his help we downloaded this font and generated some text in similar size small fonts to what we used last time.  Then we  rendered these as RGB Stripe, PenTile RGBW and PenTile RGBG to enable a comparison between RGB stripe and PenTile LCD and PenTile OLED versions.  You can see this result below.  Khalid, I hope this is more convincing.

RGB Stripe LCD - Arabic Droid Font

PenTile RGBW LCD - Arabic Droid Font

PenTile RGBG OLED- Arabic Droid Font