Archive for the ‘Web Publishing’ Category

Adobe RGB vs. sRGB – What you need to know

Friday, April 3rd, 2009

Recently I met a photographer on one of the big photo communities. His profile was full of excellent shots, many of them done on a set for a music video. He used the excellent Canon 1D mark II N, a camera model I had been using until 2008. Despite his skills to actually compose the image and find the right moments, something was not right.

I noticed a lot of subdued colors in all of the shots. The blue of the sky was rather a light purple instead of the clear blue sky I would have expected. The finish of the car was also not really bright and catchy, but looked dull and not saturated. At first I thought that this look might be intentional, to give the images that very specific subdued look. But then I looked at some of the EXIF details of the file, and there it was…

Record Mode: JPEG
Color Space: Adobe RGB

The photographer had been using Adobe RGB while saving the image files as JPEGs.

Before I start to discuss the color space issue, I’d like to recommend to you to always shoot RAW. This will enable you to change a lot of stuff at post-processing time. With essential shots for clients, I always go for the risk-free option – which is RAW. Be aware that once the JPEG has been saved, you have virtually no chance of recovering any of the details contained in the shot (that have not been processed correctly by the camera’s JPEG algo). If it can’t been seen in the JPEG, that specific detail is often lost. A RAW on my high end cameras stores 14 bits of color for each channel, that’s 16,384 individual values per color. The JPEG squeezes these 14 bits into 8 bits per channel, i.e. 256 individual values. That’s just about 1.5% of the theoretically available data for each pixel. Now you understand why saving images as JPEGs on high-end cameras is a bad idea.

But in this case, the colors are the problem, and JPEG is the cause, because only when you save an image as JPEG you need to assign a color space at shooting time. A JPEG needs to carry an information on the color space for the image so that other devices (screens) can properly display that image. That’s why there is an entry for “color space” in your camera menu, typically offering both Adobe RGB and sRGB. I know there are photographers out there who like to shoot JPEG, often because they know that they are not going to need the leeway that RAW offers. In these cases, you have to know what you are doing, or your shots turn out wrong, color-wise.

You see, the Adobe RGB space contains basically “more” colors than the plain sRGB colorspace. While the amount of data in the picture stays the same, the colors represented by the colorspace on the monitor look different! If a Adobe RGB photo is displayed through sRGB on a monitor, the colors are basically “made fit” for the smaller sRGB space. The result: bright colors look less saturated, i.e. grey-ish and dull and somewhat off.

Here is an example for this phenomenon, a photo of a hangglider at Izana mountain in Tenerife, Spain. Please note the difference in the colors. Have a look at the blue skies, the red backpack, and the brown soil. I think the difference is quite significant. But please be aware that the difference is NOT visible in a color-managed browser like Firefox. (Thanks to Wes for pointing that out in the comments!)


Saved as JPEG using the original AdobeRGB color space


Converted from AdobeRGB to sRGB prior to saving as JPEG
Mark Zanzig/www.zanzig.com

Here is another example, this time from a slide that was scanned using Adobe RGB. Again, the first image has kept its original Adobe RGB color profile while the second image was converted to sRGB prior to saving as JPEG. Do you notice any difference? I do. The pink finish of the car is much brighter, and the logo looks actually like gold, the blue sky is blue, and the number plate has better contrasts.


Saved as JPEG using the original AdobeRGB color space


Converted from AdobeRGB to sRGB prior to saving as JPEG
Mark Zanzig/www.zanzig.com

I don’t know how you post-process your images. Chances are high that you’re using Adobe Lightroom, Adobe Photoshop, or Apple Aperture. These are all capable of handling color spaces correctly, but you still need to know about color spaces, especially if you are shooting AdobeRGB with JPEGs (with RAWs you only have to care about the color space when you save the image to JPEG, see below). Lightroom and Aperture automatically recognize the correct color space from the image profile and assign the correct color space to the image.

So, you have to watch out when you open an image with Adobe Photoshop. You typically have set up your Photoshop installation to operate in a specific color space. I have set mine to use Adobe RGB. Whenever Photoshop is instructed to open an image with an assigned color profile that deviates from the standard color space, it will ask you which color space to use? None, or the Photoshop default (in my case Adobe RGB), or the assigned color space (usually sRGB). It does not matter which setting you use, because Photoshop will automatically convert the image into the selected color space (which is good).

But you always have to keep the selected color space in mind when finally saving the photo file as JPEG from Photoshop. Clients usually don’t want RAWs, TIFF is also quite rare these days. They want a JPEG, and now you know that you need a color space assigned to that JPEG. And most printers and screens are calibrated for sRGB, not AdobeRGB. That’s why you should always convert the color space from Adobe RGB to sRGB prior to handing out the photos, or publishing them on the web. Please pay attention that you should convert the photo and not just assign the sRGB color profile to the photo.

Then you and your customers get the brillant colors your high-end camera actually delivers.

Server Problems – Here’s What Happened

Saturday, October 25th, 2008


Mark Zanzig/zettpress

Yesterday we were facing yet another gloomy day with a server outage. We apologize for this.

Here’s what happened.

Four weeks ago we had to move to a complete new server as the old system was running on the same sturdy Linux box since August 2004. The operating system was outdated and apparently an invitation for hackers. And indeed someone had gained access to the system and tried to attack other computers from our system. This was spotted and interrupted by our Internet provider, and we agreed to move all sites to a new server with a current operating system.

Unfortunately, this brand new server is not as solid as the old one in terms of reliability. Two weeks ago, just after two weeks of operation, the server stopped serving pages – due to a harddisk failure! It had to be replaced by the provider, and then the O/S had to be re-installed, the accounts had to be configured again, and the backups had to be put into place.

Yesterday, like two weeks ago, the hard disk of the server was giving us error messages AGAIN. But this time our administrator, Dennis, was clearly on top of the situation as he spotted the issue prior to a total breakdown. We reported the problem to our provider, and -yep- the harddisk had to be replaced again, the O/S had to be re-installed, the accounts had to be configured, and the backups had to be put into place.

While the support team of the provider is, well, engaged it clearly does not understand the situation of the business. No sorry, no explanations, no timeframe until resolution. They just seem to be like on autopilot, sticking to their processes and rules.

This positively sucks. Big time.

We’re now working on an alternative hosting strategy. The next harddisk failure -not all that unlikely to happen within a few weeks time- will see us definitely moving to another company. I’ve had enough of this already.

Ah, in case you are wondering: this site is hosted by Server4You.

Nifty New Feature: Random Image on Homepage

Sunday, June 29th, 2008

Well, what can I say? It’s hot over here in Munich as the Euro 2008 heads towards the final match this Sunday, with Germany being the surprise finalist this year. So we at Zanzig.com should have a cool beer and celebrate (or do a couple of news shots at one of the many parties tonight).

But we also wanted to give you a cool web experience when visiting our site. :-) And so we worked on the homepage a little. It now serves a random image from a set of currently 20 photos, complete with matching background color, location name and exact coordinates. And even more: in the top right corner you’ll see the link “Show me another photo”, which does exactly that (except, well, for the unlikely case of selecting the same image again. *cough*). The widget is written in Javascript, so if you have disabled Javascript, you won’t see any of this.

Also, please note that we are now displaying ads for the friendly folks at B&H, our preferred source for professional imaging products. B&H is the world’s leading retailer of imaging products, serving professionals and consumers through their New York City retail store and through direct delivery internationally. We are confident that they will serve you as well as they do serve us.

If you want to have a look at the new stuff, here’s the link to our homepage.

Zanzig.com now serves a random image on the homepage
Zanzig.com offers to show another, randomly selected image now

SPAMfighter performance review

Friday, March 14th, 2008

Last year I started to use SPAMfighter to get rid of the growing amount of unwanted mails (read more). After an update that went wrong all the stats had been deleted, and I started from scratch. Now, almost five months later, I would like to share my experience with the service with you.

SPAMfighter statistics

The first thing that springs to mind is the fact that I have “just” about 60% spam. I have seen reports that about 80% of all emails on the Internet are spam. Not so for me (which is nice)!

Not so nice is the fact that SPAMfighter catches only 57% of the spam that hits me (i.e. 35% of all mails), and that I still have to see and block the remaining 43%. Which surprises me a bit. After all, SPAMfighter could increase their member base from 3.6 million in July 2007 to almost 4.7 million in March 2008. This bigger community should be able to catch spam better.

I guess most of the community members are consumers who do not bother to report incoming spam. One of the main problems is that there is no incentive for anyone to actively block spam, except for the somewhat cloudy, intangible benefits for the whole community. There is no “top SPAMfighter” award, no top lists on their web site, no feedback loop, no “Thank You!” mails. So, members might wonder why they should block spam at all? Where is the benefit for them? The service seems to be able to catch spam even without their help, so why bother?

Also, I am quite surprised that I still receive a lot of mails that are obvious spam (e.g. carrying certain adult keywords in the subject line). This spam could and should be easily detected by the systems, but apparently goes through undetected. I just wonder why? I would strongly suggest to SPAMfighter to also introduce keyword based filters that can be populated by the user individually, or -if the user is too lazy- by optionally using default lists provided by the community. The knowledge on the keywords has to be somewhere in the SPAMfighter systems; it’s just a matter of applying this knowledge to create more powerful filters.