Meaning that no attempt be made to cover any defects or hide unsavoury detail, this phrase dates back to radical politician and Monarch-botherer Oliver Cromwell.
As was fashionable in the 17th-century, portrait painters would soften the features of their subjects by removing blemishes and facial lines from their work (an early form of air-brushing), so the end result would always be flattering.
But when Cromwell, as Lord Protector, commissioned Sir Peter Levy to paint his portrait, he issued the artist with the following instructions:
‘I desire you would use all your skill to paint my picture truly like I am and not flatter me at all. Remark all these roughness, pimples, warts and everything as you see me, otherwise I will never pay you a farthing for it.’
The end result does include a large wart, just below Cromwell’s lower lip. These days, going sans Photoshop in magazines is all the rage, but Cromwell was doing it 400 years ago. Have some of that, Gaga.