Red Arrow
Optical Brightening Agents (OBA)

Optical Brightening Agents (OBA)

Optical Brightening Agents, also called Fluroresvent Whitening Agents, are usually abbreviated to OBA or FWA when you see them in the list of ingredients on the side of detergent containers – both domestic and commercial. Sometimes their presence is disguised with other wording.

An OBA is designed to attach itself to the surface of the fabric (they tend to be more attracted to natural fibres such as cotton and linen than they are to synthetic ones) and react with the ultra-violet portion of normal sunlight.

a15

The OBA absorbs ultra-violet light which is invisible to the human eye and re-emits it as intense white light which is very visible.

The effect is to enhance the brightness and liveliness of white fabrics making an OBA an essential ingredient when washing white bedlinen and white polyester-cotton coats for example.

However; diluting the light from a coloured fabric with white light makes it look pale and faded and the effect gets worse and worse with multiple laundering. This is because OBA builds up progressively onto the fabric surface so that the apparent fading gets worse month by month, even though the dyes themselves might not be affected. You can demonstrate all this using a simple and inexpensive bank note detector (available from RS Components from about £15). Under ultra-violet light the problem will look much worse than it does in ordinary daylight which confirms this particular fault.

There are plenty of detergents available which do not contain an OBA and these should always be specified for coloured work and coloured prints. One can expect that over half of the problems with fading of coloured prints can be attributed to OBA and not to the effects of laundering.

What our clients say...

  • “Our machines have come from several suppliers – there is a big difference in the standards of support we receive and Armstrong gets 10 out of 10 – their service has been consistently excellent over several years and when you’re as busy as we are, that’s very important.”

    Jacqui Butler

  • “It’s important to get the right equipment for the job, too small and it won’t do it properly, too big and you are wasting money, energy and space. It is also important to deal with a company you trust to supply reliable equipment and give you the support you need. As expected, the installation went smoothly, we have never had the slightest problem and I know Armstrong will deal with it if we do.”

    Colin Farquharson, St Ermin’s Hotel

  • “Our relationship with Armstrong goes back a long way, and they continue to give us excellent service and extremely reliable equipment.”

    Suzy Brandwood, The Elms School

  • “On average the equipment is working 14 hours a day throughout the week.  The new dryers are brilliant, easy to use, efficient and reliable!”

    Wendy Clayton, Chepstow Nursing & Care Home

  • “The machines are kept very busy, work well and have been very reliable.”

    Fr Oliver, Douai Abbey

  • “That’s the thing with Armstrong, if you ask for service you get it – quickly.  We know we can rely on them which is really important as the speed and quality of the laundry is vital to the hotel.”

    James Suter, The Gliffae Country House Hotel

  • “As before I am delighted with the dryers, they are really efficient and reliable and the customers find them very easy to use.”

    Shaid Aziz, Bright Wash Launderette

  • “We’re delighted with the new dryer. We pride ourselves on a very personal level of care here, keeping up with the laundry and it all coming out looking good is an important aspect of this care and this machine has been excellent since it was installed.”

    Marilyn Collins, Oaklands Care Home