Ask MetaFilter questions tagged with rgb

RGB inkjet printer color chart

sequin — Thu, 24 Dec 2009 08:30:23 -0800

RGB color reference guide. I have just purchased an Epson R1900. I need to match pantone colors & fabric swatches to create artwork. So ideally I would like to print a color reference book of all it's possible RGB colors that I can refer to as a guide to match a color. Is there an "easy" way to do this from either Photoshop or preferably Illustrator? I am a mac user. I did find a multiRIP software but it seems to be only PC friendly.

Recommend a graphics card for my new TV

muckster — Wed, 23 Dec 2009 09:59:50 -0800

Do I need a new video card to hook my PC up to my new HDTV? I have a Dell PC with a ATI Radeon HD 2400 graphics card. It has two connections, one DVI and one S-Video.

I used to convert the DVI to RGB and connect that to my Dell monitor at the max resolution of 1680 x 1050. The S-Video was connected to my tube TV, which worked just fine.

The new TV is a Toshiba 40" 1080p, so of course I'd like to feed it something better than S-Video. I tried connecting the RGB, which gives me a max resolution of 1360x768 -- but it leaves me with S-Video for the monitor, which is pretty freakin' ugly.

Here's the question: is there a way I can use a splitter or similar to feed the DVI (or RGB) into both the monitor and the TV at a resolution both will be happy with? Or do I have to get a new HDMI-ready graphics card? If I do, can you recommend one that might last me little while without breaking the bank? Under $100 would be great. I play the occasional game of TF2 but media is going to be the main use. Blu-Ray might be nice one day. I don't need to expand to a second monitor and would be just as happy cloning the same image on both screens. Thanks much.

Is HDMI hook up necessary for awesome High Def TV?

zzazazz — Tue, 06 Jan 2009 11:40:06 -0800

I have a new Samsung 1080/120hz hi def LCD yadda yadda yadda... The cable company provided RGB cable when they hooked up hi def cable. My question is whether or not I should get an HDMI cable. Does it make that much of a difference? It looks pretty darn good right now.

How is this color-changing LED array being driven?

jjjjjjjijjjjjjj — Tue, 18 Nov 2008 12:18:24 -0800

Electronics/LED Folks: I bought a few cheap, poorly-assembled LED color-changing orb-things and I'm pretty sure they're the coolest objects I have ever owned. I cracked 'em open, and damned if I know what is going on in there, but it looks simple/cheap as all hell. Help me figure it out, I'll post a build-log/parts list somewhere, and in short-order we can all be ass-deep in home-made, disarmingly sublime mood-lighting. So it's about the size of a tennis-ball, made of hard, milky plastic, and it cycles in a smooth, slow gradient between Red, Green, and Blue. (8-Second Video: Globe On, Globe Off). That's it. It doesn't look like much, and it's no danger of "blowing anyone away" or anything, but lemme tell you... it has absolutely transfixed the dozen or so people that've been to my house in the week I've owned it. I'm talkin' young, gadget-savvy folks who absolutely should know better. But we all love the stupid little thing.

Cracked it open, and inside are three 1.5V watch batteries, 3 LEDs (one each: red, green, blue), a resistor, a switch, a board, and a tiny mysterious shiny black spot.

I'd like to know what method they're using to cycle thru these colors.

This schematic represents my closest attempt at understanding the build. I'm sure you'll agree that there is at least one key element missing. It is my (unfounded, but) strong suspicion that this missing element is a very simple one (though I am very interested in answers, simple or otherwise).

MORE PICTURES:
* LED board, top
* LED board, bottom
* Switch/Battery assembly

There's a huge chance that I've unknowingly left out something of dire importance. I will try to clarify/photograph anything that is needed. I have the disassembled globe on my workbench as we speak... multimeter at the ready.

Another related question: Would there be any way to run a common anode high-power RGB LED star off of a configuration similar to what is being used in the globe above? I'm interested, very generally, in novel methods that can be used to drive RGB (or separate "R, G, and B") LEDs. I'm slowly getting the hang of PWM and microcontroller/Arduino-based methods, and I like what I've learned... but I've not come across much that deals with any other methods. Thanks to all.

RGB to CMYK advice needed

merocet — Fri, 14 Nov 2008 08:11:58 -0800

I'm working with a client who has an existing web logo designed the majority of which is three primary colors in RGB. So left to right it's a vertical stripe of Blue (#0000FF) next to a vertical stripe of Red (#FF0000), next to a vertical stripe of Yellow (#FFFF00). This logo now needs to go on business cards (plastic ones) and so needs to convert from RGB to CMYK in order to be printed. Problem being that the CMYK gamut just doesn't do those eye popping RGB turned up to 11 primaries so conversion leaves a lackluster product and the client on seeing the drafts in PDF with the colors converted is not impressed. Ideas for saving this one? CMYK versions of those colors that contrast in a similar way to their RGB equivalents? Recommendations for printers (online or in NYC) who can do 3.5" x 2", rounded corner, double-sided, plastic business cards with special inks? HELP!

Converting RGB to CMYK

aisleofview — Thu, 10 Apr 2008 05:00:02 -0800

I am designing a card in photoshop, starting out in RGB then converting it to CMYK for print. The RGB looks vibrant and beautiful but the CMYK conversion is lacking contrast and the colors are washed out. Anyone have any ideas on how to maintain the beauty of the RGB image in CMYK?

Converting CMYK JPEGs to RGB

drill_here_fore_seismics — Wed, 15 Nov 2006 06:01:04 -0800

Recommended methods for converting CMYK JPEGs to RGB JPEGs, ideally batch conversion? I have about a hundred JPEGs in CMYK, and I'm looking for a straightforward way to quickly convert them to RGB. I'm using Windows XP and don't have Photoshop. Is there a method or a tool (preferably Freeware) that can do this?

Failing that any advice on simple ways to convert CMYK to RGB, even one image at a time, would be much appreciated.

The Mystery of the 4 Color JPEG

lodurr — Thu, 28 Sep 2006 11:26:24 -0800

Is there actually such a thing as a "4 color JPEG"? And if so, why? Apparently a lot of design firms supply "four color JPEGs" as part of their standard logo sets. These are produced out of Illustrator by saving with a CMYK profile. (AFAICS, only Adobe and Apple products can read the resulting files with proper color profile information. Most browsers simply treat them as broken files.)

So, my question is this: Is there actually a good reason to do this? Is there any software that's used for things like signage or layout that works better with JPG than with PNG or TIFF? (Or, better yet, EPS?)

When 3 CRTs are side by side, why does the color seem to be off in red, blue, and green (individually)?

maldrin — Mon, 14 Aug 2006 09:43:18 -0800

When 3 CRTs are placed next to each other and are showing exactly the same image, why does it often seem that one is redder, one is greener, and one is bluer? This is something we've seen where I work on multiple hardware configurations and in random order, but always one of each in a three-channel configuration. It seems to be true whether all three CRTs are hooked to one PC, or if all three are hooked to separate PCs. I’m not well versed in color calibration or video signals, and I found tons of great information about calibrating here, but no one seemed to describe this particular issue. I was curious if anyone has seen this and has an explanation for what causes it and how to predict or deal with it. In part I wonder whether it’s simply an optical illusion, or if possibly this is caused by video interference between the monitors when they are in close proximity to each other.

WTPh?

maggieb — Wed, 26 Apr 2006 18:07:38 -0800

What is this cryptic image? Two sets of RGB dots.
Greyscale swatches of light.
Directional arrows.

Disclaimer: This is not homework or any type of test or contest. My friends and I are curious but baffled. The image is not presented to us in context.

Image hosted at ImageShack

Why do computer screens etc use red, GREEN & blue?

TiredStarling — Wed, 16 Feb 2005 12:50:34 -0800

The primary colours are red,yellow & blue. All other colours can be made from them. Why then do computer screens etc use red, GREEN & blue?

Deleting a Swatch

silusGROK — Fri, 30 Apr 2004 12:22:47 -0800

Adobe 1.5.2 (Mac OS 9x). Deleting a swatch... I have an RGB document with a single full-color image and two spots (Blue and Black). I'm converting the document to CMYK for print: I've swapped out the RGB JPG for a CMYK TIF, the Black swatch is fine, and now I want to delete the Blue (RGB) swatch and do a global replace for the Blue (CMYK). But InDesign isn't allowing me to delete it, nor to modify.

Suggestions? Adobe doesn't support 1.5.2 any longer, and their online help has been purged of relevant documents.