RPS Imaging Science Group

Spent a great day yesterday at the Sign & Digital trade show at the NEC – see <http://www.signuk.com/> . While the show covers the whole plethora of supplies for this industry I was interested in some of the wide format printers and media on show. Here are my highlights.

First of all the HP Designjet L65500. This is a stunning unit featuring their latest Latex inks. The inks are water based so there are no solvent fume issues but the product still works on uncoated media. However, 12kW of heaters adds up to some electricity consumption! And thanks to Rana Raychoudhury of HP for spending time with me to show me the features of the machine.

Also on show were a wide selection of UV inkjet units. I was particularly taken with the smaller units that contain UV LEDs to cure the ink. One I particularly like is the Roland VersaUV LEC-300. Unlike the larger units this is rated at only 320W so can be run from a standard 13A socket. On a larger scale the guys on the Screen booth had their UV system on display and as usual were great to talk to.

Finally, I took a further look at the HP Designjet Z6100. This is a worthy successor to the earlier HP5000 series. It looks like a great photo printer.

On the media side I spent some time with the guys from Harman Technologies. Harman is what became of Ilford after receivership and they continue the tradition with some high quality pop up display media on show.

Last day for this show so catch it while you can. See you there next year!

Centaurus A Credit: X-ray: NASA/CXC/CfA/R.Kraft et al.; Submillimeter: MPIfR/ESO/APEX/A.Weiss et al.; Optical: ESO/WFI

As this blog is about Imaging Science (if only a pixel of it) it seemed logical to me that we need some pictures to illustrate this. We then run into the complicated issue of image copyright.
Most of the pictures on this site were taken by me so I gave myself permission to use them. Some of them were commissioned by me from Peter G Crosby of Right Eye Pictures (see http://www.myrighteyepictures.com/).
However, some of the really splendid ones come from hugely complicated and expensive imaging experiments, particularly those concerned with astronomy. Fortunately these are freely available from the various web sites with explicit permission for their use.
For example the European Space Agency makes images available and you can find the copyright issue covered under http://www.esa.int/esaCP/SEMK95VZJND_index_0.html . Likewise the composite Chandra image shown above, available from http://chandra.harvard.edu/photo/2009/cena has similar availability. You will also find statements about Spitzer image rights under http://www.spitzer.caltech.edu/Media/mediaimages/copyright.shtml
These images are made available for non-commercial purposes which fits well with the educational mission of the RPS and this blog. I do take great care to get the image credits right too.
Although these images have great educational purpose they have (for me at least) great artistic qualities. They are also a wonderful example of Visualisation where a difficult concept is demonstrated by an image. In the above case the X-ray image is illustrated in blue, the submillimeter in orange and the optical in “real” colour.
Now that is multispectral imaging!

The primary and secondary mirrors on Herschel © ESA

I am waiting for the launch of the next space telescope – the ESA’s Herschel telescope. This platform is distinguished by the fact that it contains the largest ever telescope mirror to be launched into space.
It is a very different unit to Hubble. For a start it operates not in the visible but in the far infrared and sub-millimeter wavelengths. As a result the primary mirror is not made of optical glass as is common with visible wavelengths but is made from silicon carbide. In a novel engineering design this optical element was made by brazing 12 “petals” together to make the optical surface.
Although the launch window opened 10th April and the verification of operations procedures has been completed some concerns have arisen that require some final checks.
Once they are all sorted the launch vehicle will be fuelled and the detector cryostat, necessary to keep the detectors at low temperature will be filled and off we go. I am looking forward to the first pictures!

Earlier this month I wrote about adding colour to monochrome images. I have just been reading a paper from the 16th Color Imaging Conference – see http://www.imaging.org/conferences/PDF_PROGRAMS/CIC16_Preliminary_Program.pdf . The authors, Clément Fredembach and Sabine Süsstrunk looked at the way in which near infrared (NIR) images can be integrated with the “normal” colour image to produce a subjectively pleasing result. Along the way they present some of the interesting characteristics of the infrared images that can be taken with consumer digital cameras. After looking at Rayleigh and Mie light scattering they illustrate some of the issues with white balance caused by the “tail” of the spectral response of the colour filter array. They then look at potential methods of blending the NIR filtered image into the colour version through substitution into one channel of a HSV, YCbCr encoded image plus some PCA and frequency analysed images. They used psychophysical evaluations to assess the results. The found that combining HSV and YCbCr encoded images with the NIR data using a method that depends on the direction of the modification gave the most pleasing results. However, their psychophysical evaluation found that the preference was strongly user dependent.
Beauty in the eye of the beholder indeed!
The paper was featured in the IS&T Reporter and a free version can currently be found under http://www.imaging.org/pubs/reporter/

Just got a note from ISO that the new version of ” ISO 3664 – Graphic technology and photography -
Viewing conditions” has just been published. This is an important standard for those working in both photography and Graphic Arts.
I will be back with more details when I get my copy!

I received news this week that I had been elected Conference Vice President of the Society for Imaging Science & Technology (IS&T) – see www.imaging.org. My thanks to all who voted for me. I hope we can all work together to greater benefit of Imaging Science through these economically troubled times. My 2 year term starts in July.

I have written previously about the value of networking and organisations like the IS&T, RPS and IoP working together. Time to put it into practice!

Hythe seafront in the Infra Red © Alan Hodgson

Just back from a 1 week holiday on the South coast of England. Last time I was here I brought along my modified Photosmart camera to take the infrared picture above. You can find more details about this camera in my blog article “Megapixel Mania”.
This time the visibility was rather poor and as a result the photo opportunities were few and far between. Instead I spent some time considering the various aspects of Imaging Science in the Infrared.
Back in my time in Silver Halide photography I worked on products sensitised in the near infrared for aerial survey and holography. As a consultant I worked with a company supplying image intensifiers working in this region.
We now have an explosion of Infrared imaging on the back of digital technology. In particular we have space based imaging platforms working across a broad spectrum of wavelengths conducting imaging and spectroscopy.
I plan to revisit all these topics in future blogs as we move towards the Infrared 100 anniversary.

The Institute of Physics Printing and Graphics Science Group in collaboration with the University of the Arts London MATAR Centre (see http://www.matar.co.uk/) organises a periodic International conference entitled “Preservation and Conservation Issues in Digital Printing and Digital Photography”. We were due to have our 4th meeting in April this year but had to postpone it due to difficulties speakers had in committing to present in these financial circumstances.
We are currently looking to reschedule for 2010 where we once more propose to invite and attract conservators, digital photographers and printers for our 2 day meeting. It has a complementary focus to the IS&T Archiving meeting (see articles dated 6th April and 26th March) in that it focuses on prints rather than digital files. In addition much of the emphasis is on preservation for the long term rather than the (comparatively) near term issues facing consumer photography.
One of the areas I hope that we focus on is how we estimate a print life. Degradation mechanisms such as thermal, humidity, light and airborne pollutants such as ozone are well documented in the literature. There was a particularly good summary of the issues involved in reconciling these from Torrey Pines Research at the last NIP conference – see http://www.imaging.org/conferences/NIP_DF2008/details.cfm?pass=136.
For high end conservation of some systems it may be enough to simply measure thermal stability and use the Arrhenius relationship to estimate a print life. This could work because environments can be set such that light and pollution can be removed and the effect of humidity minimised. But you try taking a print down to absolute zero  – you will always have some thermal effects!

A fascinating article in The Times today. The earliest colour picture of Edward VII has been found, taken by Lionel de Rothschild in 1909. It was taken using the Autochrome process and the image is on the National Media Museum web site – see http://www.nationalmediamuseum.org.uk/autochrome/Notable_Photographers_detail.asp?PhotographersID=9.
The process was invented by the Lumiere brothers. In later years their company became part of Ilford Ltd where I came across their process as part of the anniversary celebrations so this is a blast from the past for me!
You can find more details on the exhibition and a resource on Autochromes under http://www.nationalmediamuseum.org.uk/autochrome/index.asp.

A colleague pointed out a really interesting work “Fingerprinting Blank Paper Using Commodity Scanners” – see http://citp.princeton.edu/paper/ . It is due to be presented at the IEEE Symposium on Security and Privacy next month.
While the paper concentrates on security aspects the techniques therein look to have wider applicability. They show that commodity flatbed scanners can very effectively characterize paper surface texture using 4 scans at 90 degree intervals.
Looks to be a low cost and robust method to characterize the surface of paper!